Okay Gale, thanks for the extra information. I was asking about the color (yellow would be Lutino) because the Lutino Tiels, genetically speaking, nearly always have a bald spot just under their crest. A Lutino gene somewhere in the family tree could account for this, even though the baby may not be full Lutino. If the feathers are missing on top of it's head, it will have to be genetic, (assuming there is no skin damage and no indication of it being plucked) or it is being plucked by the parents. That would not be an unheard of circumstance, especially if the male is wanting the female to mate again and he is trying to run the baby out of the nest. If you know beyond all doubt, there is no pecking and no "chick abuse" going on, then it's either genetic, or it will fill in later as the chick matures. If there is any possibility at all the chick is being abused, you have no choice but to separate it from them and finish weaning it out yourself. Lucky for you and it, it is old enough you won't have to try to learn proper hand feeding techniques using a syringe. That is very dangerous to a chick if the hand feeder is a novice. If this becomes necessary, you can get baby bird weaning formula from the pet store. It is in powder form and you only mix the smallest amount at a time with warm water. It should be about the consistency of runny oatmeal. You can offer it to the baby with a plastic picnic spoon or in a shallow saucer. Just don't ever use any as a left over. It grows bacteria quickly so offer some, and what is not eaten right away, pitch it. They all also need some additions to the diet. I'm surprised yours like any fruits at all. Generally speaking, Tiels don't care for fruits but that's great if they do. They should also be getting plenty of vegetables, leafy greens and much more, everyday. If their diet is more than about 30% seeds, they have been struggling to be able to feed chicks properly and that could be another possibility they are encouraging the baby to fledge and get out. Cuttle bone, being available all the time is mandatory and I'm glad to hear you were providing that. Hens laying eggs can get in deep, life threatening. situations very quickly, without enough cuttle bone and other calciuim sources. I urge you to start right away offering them other foods and be persistent. They may refuse it for a good while but their long term health depends on getting the seed portion of their diet cut way back. Seeds, and especially sunflowerd seeds, are very high in fat. That leads to liver disease, (Hepatic Lipidosis) and other issues. I'm going to give you the same links I usually give to new Tiel owners that will cover the diet, the consequences you can expcet from inadequate diet and some other issues. I hope some of it will be helpful to you. In the meantime, keep a close eye on that baby and be prepared to separate him to his own cage right away if necessary. You could go ahead and start offering him some hand feedings, in any case. That will start taming him down much quicker, and much easier. Let me know if you need anything else and good luck with them. Patricia
These first 4 links talk about the weaning process. Other species are mentioned but the basics are the same for all.
Click here: Breeding Lovebirds Part II Handfeeding Weaning and Socializing
Click here: QuakerParrots.com - Abundance Weaning
Click here: Winged Wisdom Pet Bird magazine ezine - Bountiful Weaning produces quality pet birds and parrots
Click here: Abundant Weaning & Fledging
Click here: BirdsnWays - Articles & FAQs on pet birds, pet parrots & exotic bird species - Cockatiels
Life After Weaning - Your Companion Bird and You
Caring For Your Pet Cockatiel
Fatty Liver Disease in Cockatiels
Click here: Cockatiels as Pets - Choosing a Cockatiel, Cages and Feeding
Click here: More Birds Die as a Result of Air Fresheners: That Stinks!!
Click here: Alerts Dangers and Toxins for Pet Birds Parrots
Click here: Bird; Birds: Safe, Toxic Trees, Woods. Safe Tree Wood. Poisonous. Parrots.
Click here: Toxic and Safe Plants/Trees for Birds - Household Poisons
Click here: Birdsnways - Safe Plants & Trees for pet birds, pet parrots &exotic birds Potentially Toxic Plants
Toronto Humane Society :: Common Poisonous Plants
Click here: Bird Proofing Your Home: Household Hazards for Birds
Click here: Bird Proofing Your Home - Avoid These Pet Bird Hazards