I bought a baby cockatiel a week ago and the seller said it was about three to four weeks old. The problem is, it doesn't beg for food and wants to eat if it is not very hungry(like 8 hours no food, if it begs for food but only eat 5ml). I'm still using the seller's formula and I follow all the instructions, I have to use a syringe to force it to eat, if I use a spoon and insert into its beak it would just eat 2ml and step back to refuse to eat, I really don't know why it doesn't beg for food and doesn't want to eat, it is still growing and looks healthy as I force it to eat the formula every day, I searched all websites and cannot find the answer unless the formula I got from the seller is bad, I did contact the seller and he told me that I'm lucky to have a baby cockatiel that does not beg for food because some babies don't stop begging, he asks me to keep forcing it to eat. Meantime, a guy from another forum said that the seller is fooling me because begging for food is its nature, the baby should always want to eat, if a bird does not want to eat much it means it is ill, the seller definitely knew this baby was not okay and is never going to admit that there is an issue with his bird, he believes that I should return the bird immediately if possible. However, I was been asked to pay cash only and he didn't give me a receipt, he refused to let me pick the bird the reason was I will scare those baby cockatiels which will cause them to die, he also said he selected the biggest one in the nest but seems not true by comparing to similar age cockatiels online. I don't know what is causing it to lose appetite, what should I do?