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Cause, Prevention & Treatment
Susanne Russo

According to the veterinarians with whom I have spoken, roughly eighty percent of the Cockatiel babies seen have some form of yeast, a bacterial problem, or both. These statistics are high, yet I have found they can dramatically be reduced to five percent or less!  Having raised over six thousand babies, I have discovered several of the causes and would like to share some of my solutions for dealing with this problem that needlessly claims the lives of so many babies.

Yeast is the #1 cause of death in baby cockatiels. Yeast has also been the primary reason for breeders and hobbyist 'getting out of 'tiels' because they couldn't cope with the heartbreak of continually losing babies. I can't answer as to why yeast is predominately a problem with cockatiels versus other species of babies. As a species cockatiels are more prone to stress and changing conditions such as management, diet, weather, pairing, caging, etc. To further add to the confusion the initial diagnosis is 'bacterial', when in reality the bacterial problem is a secondary infection generated from stress to the system from an overgrowth of yeast.  It's the stress and conditions which result in yeast as the 'primary' infection, then 'bacterial' as secondary.

Once causes of stress are resolved cockatiels are very hardy birds and are resistant to most yeast and bacterial problems!

With this article I will use the word 'yeast' to also include other terms commonly used such as candidia and fungal infections.

First we need to understand how a yeast problem develops.

You've heard the saying 'It's in there.'  Yeast, like bacteria are on and inside all living animals and birds. It is considered a normal environmental organism and normal inhabitant of the avian digestive tract. In most reference books yeast is listed under Fungal Diseases. The causative agent is Candida albicans which is opportunistic yeast that can cause a variety of problems associated with the avian digestive tract, crop in adults, and crop disorders with babies. In most instances a bird can live its entire life without the resident yeast causing a life-threatening problem.  When situations present a form of stress the system can respond with a lowered immune system or an upset of the normal bacterial flora, which thus can create an overgrowth of yeast. It is this 'overgrowth' of yeast that can quickly become life threatening if it is not recognized and corrected. In other words: What is normally good and beneficial can work against the bird when something triggers an upset/overgrowth.

A culture can determine how much of an overgrowth of yeast there is and the proper course of treatment. It will also show overgrowths of bacteria resulting from the yeast overgrowth. If you looked at the culture report you will be very surprised at the amount of bacteria listed in addition to yeast!  What the vet 'reads' from this are the levels above normal. Most culture reports will also have another section that lists recommended medications that a bird is sensitive (effective) to and resistant (ineffective) to.  You can ask for copies of culture reports.  I've found they are a very informative learning tool in studying the various bacteria found in the bird.   I've used the listings to research and study each organism to learn how to recognize the symptoms and how to properly correct or treat.

Much of the current information available is outdated, and in some cases impractical.   In the early '90's, when yeast showed up in cultures, levels were not really taken into consideration, therefore vets automatically prescribed an anti-fungal (yeast) therapy. Up until the mid '90's is was common practice to encourage breeders to flock treat if one pair or clutch had yeast, meaning all the birds got treated whether they needed it or not. Flock and group preventative treatments rarely solved the problems. It was not even considered to treat each bird on an individual basis. Rarely were there suggestions or solutions given to reduce or eliminate outbreaks of yeast. After studying thousands of
babies in the nest I have noticed that stress is the most common factor to yeast in nestling Cockatiels.  From numerous observations of my own birds I have found that yeast is specific per baby.  It is not communicable to the others in the clutch.

I have used the word 'stress' quite frequently. My definition of stress is anything that can directly or indirectly cause something inside the bird to change or react to a situation or condition. Since yeast mainly effects babies either in the nest or while handfed I will focus on possible cause, and what to look for, and suggest preventative measures.

Interestingly from observation of over 6,000 babies in 5 years, it is rare for a baby to directly contract the yeast from the parent bird. Most yeast problems in the nestbox are what I call system-induced, meaning that a form of stress generated the yeast.

The first 10 days of life are when the baby is more at risk to develop yeast overgrowths. Being aware of simple precautions and things to watch for makes a dramatic difference in baby survival. One thing that will help both yourself and your birds is to get them used to you looking and poking around in the nestbox.  When you first set them up do a nestbox check as often each day as you can.  This 'conditioning' helps later on when the eggs are piping and the babies are hatched. A baby could be perfectly fine in the morning and by afternoon either be sick or dead. So many things can happen in a matter of hours! Simple preventative measures, along with knowing what to look for and what to do brings joy and satisfaction rather than the heartbreak of another baby lost.

Some major causes of stress that generate a system-induced yeast.

1. Poor parenting or feeding skills: New parents or forced (not bonded) pairs are less likely to have a good parenting response. They may not know what to do, or may not even feed the baby.

Each pair responds differently with a new hatch. A baby can go without food for up to 12 hours when hatched. They may be able to go this long without first being fed, but they can't go without the warmth of a parent covering them.   Warmth is a priority over food during the first few hours of hatching. During this time the baby is living off the nutrients from the egg yolk sack which was absorbed prior to hatching. If you look at a newly hatched baby's abdomen you will see the yolk through the skin. The parents will feed a small amount of liquid from their crop, which will put beneficial bacteria into the baby.   Some parents will do this right after hatching or they may wait several hours. The first few feedings will only be visible by a small swelling to the crop at the base where it meets the body of the baby. With each successive feeding the parents will put more food in the crop to increase the crop size. If the crop is totally flat looking for several hours I would give the baby a drop of warm distilled water. When it is obvious that the parents don't know what to do or will not feed I will foster it to another newly hatched clutch, or pull to handfeed until the baby appears to be strong and will beg prior to being fed.

Note: When you foster a baby only feed it half a feeding. The reason for this is so that it is still hungry and begging when put in with the clutch. Parents will ignore a baby that does not beg, and feed only the ones that are crying and stretching their beaks up to be fed. If a baby has no feeding response even when you try to handfeed it something is wrong. Fostering a baby that has no feeding response is only dooming it to die.   When a baby will not beg the parent birds will gently nip a wingtip to get it to cry and open it's mouth, then they will try to feed it. If it does not pump/bob when the parents are trying to feed they will bite down harder on the babies beak to get a response.  If there is still no pumping response each time they 'nip' the baby on the wing tip or beak the bite is harder to the point of damage or death in their frustration to feed it. If found dead you will notice that the beak is bruised and purple looking, the crop empty, and possibly the wingtips damaged. If you find one that is obviously not being fed and have to pull it, the first priority is to keep it as warm as possible, then examine it's mouth an crop. (Details are given later in the article on what to look for.   Also refer to some of the photos posted for comparison.) The lack of feeding can be enough stress to the baby to quickly generate a system induced yeast response that can harm or kill it within a day.

2. What and how a baby is fed can cause problems. Some parents will give a baby all seed and very little water. Most times this is noticed with the last few chicks in a clutch. The crop will have a hard doughy feel to it. When the crop is gently squeezed it will leave an indentation of where you pressed. In this instance a baby will quickly become dehydrated from lack of fluids. When I see a dehydrated baby I will supplement feed it a very dilute formula to get additional fluids into it. 

Over time dehydration can cause the baby to not develop normally and have a stunted look. A stunted baby will have an oversized head, bulging eyes, and undersized wings and feet, in addition to a low-grade yeast and/or bacterial problem.

On the other hand some parents can give too much fluids which will result in not enough nutrients for the baby and/or an over stretched crop. These parents tend to eat more of the soft foods that are available to them. Excessive amounts of fluids can also result in sour crop and/or crop stasis. I've found that with soft foods the parents tend to be 'sloppier' in how they feed. The baby will often have food crusted on its beak or in its mouth. Sometimes the food can also be matted on the head and the 'down' on the baby's body. Therefore the next time the baby is fed the new food becomes contaminated by the
old/existing food on the beak and mouth. The food build up should gently be removed from the face and beak with some warm water on a soft cloth or a tissue. From my own personal experience most of my yeast problems in the nest came from soft foods. I've found that the best time to give soft foods (egg food, rice, corn, etc.) is first thing in the morning when the birds are hungry. After an hour remove what has not been eaten.
Any type of soft food can quickly build up harmful bacteria. I have found that limiting both the amount and the time that the cockatiels have access to them has reduced my yeast problems by 85%! Therefore, too much or not enough fluids, erratic feeding and crusty mouths create a stressful situation for the baby. Carefully monitoring this during the first ten days greatly reduces the chances of yeast.

3. Chilled babies: When a baby gets too cold it has to rely on its own body reserves to generate heat. If there is food in the crop this also gets chilled which also slows down digestion. Most parents are good sitters. When a baby is small one parent will be covering the babies while the other parent is out of the box. For a short period of time you may see both parents out. Sometimes a baby can get 'lost' from the clutch and not be able to get back. The parents can move eggs but they can't move a baby back if it is too far from the clutch. Most babies back up when they have to eliminate. If they back into a low spot in the nesting material it is hard for them to get back to the clutch. If chilled too long they die. As the babies start hatching I will rearrange the bedding slightly so that the bedding in the box is bowl shaped - meaning that the babies are at the lowest point and the edges are the highest point. This tends to keep the clutch together, with less chance of a baby getting separated and chilled. When you find a chilled baby never assume it is dead.  First warm it up on a heating pad set to a low temperature. If there is still life it should be able to move and be back on its feet within 20 minutes! If the baby has food in the crop give the baby a drop or two of water, massage it to mix with the crop contents, and return it to the clutch.  If it is empty feed it a little handfeeding formula.  If it has a good feeding response return it to the parents so that they can finish feeding it.  If the baby is lethargic or is not interested in being fed I will give it some Nystatin first, then some formula using Pedylite as the water for mixing, the feed a small amount. Keep the baby warm and monitor the droppings to see how frequently it is eliminating. Thus, chilling is another form of stress, which can result in yeast.

4. Bedding: I have found that the amount of bedding in the nestbox does makes a difference to the babies. Not enough can result in cracked eggs before the baby is hatched. When the baby is on bare wood it is harder for it to stay warm, and maintain body temperature when the parents are not sitting. There is also the risk of 'splayed legs' from not been able to get a good grip with their toes. Two to three inches of pine bedding will add additional insulation from cold, and the bedding tends to hold some of the babies body heat to keep them warmer. Most nestboxes tend to stay dry. The dropping will look like clay balls when dried.  What you don't want to see is excessively wet bedding from the baby's droppings.  Either the parents are feeding the babies too much water or this could be an indication of yeast and or bacterial problems starting. A sour smell in the nestbox is another indication that a problem is starting.  When the bedding is wet it is harder for the babies to stay warm. The babies vent should be clean and free of feces. When the vented is crusted over the baby will kick at it to remove the build-up.  Many times this can create bleeding.   Gently clean the area with warm water, and apply Neosporin. If you see a crusting around the vent most likely this is from too much soft food, specifically egg/nestling foods.  Cutting back on the amount given tends clear up the vent area.

In summary, poor parenting and feeding skills, how and what it is fed, chilling, and nesting material all are contributing factors to the health and well being of the babies while in the nest. From my own personal observations and experiences monitoring these things has almost eliminated yeast problems in the nest. Always keep in mind that when a problem occurs, within a matter of a few short hours things can become critical, especially with smaller babies.  Simple observation is one of the best defensive a breeder has against losses in the nest.

Ideally, what you would like to observe during the first 10 days is a clean healthy looking mouth and beak, and a slightly firm crop. The tongue should be dark pink and be free of any white discoloration or food under it. The skin color should have a healthy pink look. The down should be fluffy. The body should have a plump rounded look. The crop skin will have a transparency so that you can see the crop contents. The crop when full should feel firm, and you should be able to see a good mix of the seeds and fluids. The texture of the crop skin should be smooth and free of prominent red veins. When fed, the baby should be quiet and will huddle with its clutchmates while sleeping. 

Once your eye is trained on what a healthy looking baby looks like you will be able to spot any changes in the look of the baby before problems get out of hand or become life threatening.

Still this is not enough!  Sure, these are a few suggestions on how to prevent stressful situations for the baby, and what a baby should look like, but you still need to know how to recognize yeast when it does start.

Recognizing yeast

Before I say anything else, please don't use this information as a means for not consulting with your avian vet. The information is meant to be guidelines for observing possible yeast infections. If you are unsure of what is wrong bring the babies (please keep them warm) to vet for treatment. Use this time to discus with him/her what to look for and do in future situations. Several of the treatments I will suggest can be obtained from your vet.

Half of the battle is knowing how a healthy baby looks and acts. The other half of the battle is knowing what to look for. When a  problem starts you will notice changes to how the baby looks and acts. A hungry or sick baby will always cry and act restless with its wings outstretched.  First determine if the crying is because it is empty. If so you can supplement feed it a little handfeeding formula and see if it settles down when it is returned to the clutch.  When content it will snuggle with it's clutchmates and go to sleep quickly.  If not, some problems may be starting.

If the baby has food in the crop and the body feels warm look at the mouth and the crop to see if there are any changes. Are the crop contents visible through the crop skin? If the skin has an opaque/whitish cast yeast could be forming. Is the down still fluffy, or does it have a wet stringy look? If the crop looks small for the age of the baby, and has a thickened look, again this is yeast. A normal crop has a flat look and will 'contour' to the body when totally empty, and a very slight pouch when there is a tiny bit of food. The skin will feel tissue thin when felt between the fingertips. When a crop has yeast it is most noticeable when the crop is empty. The skin will feel thickened. You may also  see a 'lumpiness to the crop, and feel 'knots' of soft tissue masses inside the crop. Advanced yeast will cause the membranes to thicken the crop interior and the texture would be similar to a Turkish towel. As this thickening progresses the crop interior shrinks and it can not hold very much food. Many times this can cause the baby to regurgitate. Try to put the Nystatin in the crop when it is empty.  Gently massage the crop skin so that the Nystatin makes good contact with the inside surface of the crop.  Do not feed the baby for at least 15-20 minutes.  Note: Nystatin is only effective to the areas it comes in contact with.  It is not absorbed into the skin/tissue of the crop or digestive tract.  When yeast is advanced it becomes systemic -- meaning that is has traveled into the major organs, bloodstream and tissues.

When this happens a stronger anti-fungal medication is needed, such as Diflucan and an antibiotic. Your vet can determine the extent of the illness and prescribe the proper medications and dosages.

If the crop skin also has visible red veins showing a secondary bacterial problem is starting, in addition to yeast. Most likely the baby will also be showing signs of dehydration.  The body will have a reddish look, and the toes will start to get very thin and 'stick-like' looking. Your vet can recommend the proper antibiotic in addition to an antifungal treatment. Note: When a baby is sick and dehydrated the dehydration must be corrected first before any antibiotic treatment.   If hydration is not corrected this will greatly reduce the chances of a successful treatment.

Again, heat is vital when a baby is ill.  Humidity is also vital if there are indications of dehydration.  Some basic guidelines for temperatures are: Unfeathered babies under 10 days old need a temperature of 94, older chicks at 90, and adults at 85 degrees.  Humidity should be approximately 70%.  You can either pull it for handfeeding and treatment or leave it with the parents and treat. As to myself, when the baby is under 10 days old, I will treat it while it is in the nest rather than pull it. Somehow I have always found that the survival has always been better with the parents. Rarely do I pull babies this young for handfeeding and treatment. Medicating at this age is also difficult when using a syringe. My personal preference is to tube feed the treatment into the baby, using a 2" length of size 10 Fr. Catheter tubing attached to a 1 CC syringe. You can ask your vet to make/supply you one. There is less risk of aspiration this way.

If the inside of the mouth has a white or 'cheesy' look to it you can use a solution of 50% Nolvasan and 50% water to gently swab (with a dampened Q-tip) the mouth twice a day.  Also try to swab as far down into throat as possible.    Do not try to 'scrub' the build-up loose; just lightly swab the mouth, and throat.  As long as the baby has a yeast infected mouth anything it is fed will be contaminated before it enters the crop. Also treat, and massage the crop with Nystatin 2 times a day. Usually by the third day the solution will have 'lifted' the yeast from the skin surface and chunks will come loose while swabbing.

The hardest problem to correct is a crop that looks oversized and has very watery contents, and a 'gassy' bloated look to it. The first thing that needs to be done is to fully empty the crop. If this is not done, it is nearly impossible to save this type of baby. If you have never emptied a crop have an experienced breeder or your vet show you how.

There are two ways to empty a crop: either manually holding the bird head facing downwards, and expelling the food, or using a crop tube/needle. After the crop is emptied I will give some Nystatin and a small amount of handfeeding formula. If I have other nests with babies the same size I will foster the baby to another clutch and monitor it several times a day. Sometimes a different 'feeder' can remedy the problem. If you have to pull for handfeeding and treatment remember to keep the baby in a small warm container.   Most likely the crop skin will be overstretched, so you will feed less amount and more frequently to (hopefully) allow the skin to shrink to normal size. If there are also signs of dehydration, used a rice based electrolyte as the liquid in mixing your formula. When a crop is grossly overstretched it will droop below the opening to the digestive tract. This opening is located at the base of the neck. When this happens the food can not get into the digestive tract. Prior to each feeding the old food has to be removed from the crop. One excellent remedy to this is fashioning a 'crop bra', which is used to lift, and support the crop so that the crop is in the proper position for the food to enter the digestive tract. The bra also aids in support of the tissues and allows them a chance to heal and shrink to normal size. A vet can fashion an H shaped bra, and fit it to the baby. It usually takes up to 2 weeks for crop to return to normal size.

So far we have only discussed some of the problems that can occur in the nest.  Yeast can also create havoc once a baby is pulled and being handfed. Luckily it is easier to prevent when handfeeding!

Babies in Trouble....   (these photo's were taken for AFA Watchbird...and are illustrative for the above article)

More babies with problems

Susanne Russo

Cockatiel Photos:
And More Cockatiels
Babies and Young Tiels
Cages and Flights

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Thanks Susanne for this excellent article!!!

Sibylle Faye

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