Hi Kazi,
The earliest a cockatiel should be fully weaned is 8 weeks old. And really this is much younger than a wild cockatiel would be weaned. In the wild, the parents would be teaching it to forage for food as well as still feeding it some. I prefer to see them getting formula until they are at least 12 weeks old.
Formula has more nutrients than the food you will wean him to. He needs the additional nutrients to continue growing and developing. Cockatiels are technically still going through some physical and mental growth and development for the first 2 years. But they only need the added nutrition of formula until they are 8-12 weeks old.
You should start by offering a nutritionally balanced food like pellets. Seeds do not provide much nutrition at all, so it is best to just not offer seeds, unless you have access to our foraging diets. Also offer chopped veggies, some fruit, greens and some warm soft food – cooked brown rice with veggies mixed in is good. He needs all of these foods in the cage, as well as fresh water. He needs to have the option to try all kinds of food, and he will waste most of it, but this is the best and healthiest way to wean him. You can also mix some thick formula and offer it in a small cup, and some cooked eggs. These two foods are only during the few weeks that he is weaning.
Weaning is gradual – you don’t force him by withholding formula & starving him. It may have become tiresome for you, but you took on this responsibility and you need to wean him properly so he doesn’t end up with behavioral issues and trust issues. Weaning should not have any effect on his bond with people. If anyone told you that, then they are forcing – which means starving – their birds into weaning.
Put the foods listed above in his cage first thing each morning, before you hand feed him. Leave him alone with these foods for about an hour. If he can see or hear you, he will just beg for formula. Then feed him formula and repeat this before his next hand feeding. Soon he should be only needing formula twice a day – morning and evening. And then he will probably cut back to once a day, and then he will get to where he refuses the formula and that means he is weaned.
As for sour crop, it’s OK for him to self feed if he has also eaten formula. But don’t handfeed him again until his crop is almost empty. It doesn’t matter what you think the schedule should be – birds have their own schedule, so never hand feed formula on top of undigested formula.
Thank you for asking Lafeber,
Brenda