Hand fed Cockatiels usually do not have problems like that when being hand fed. If you are syringe feeding, it is normal for her to swallow some air. If she isn't chirping she isn't hungry any more. There is a chance you could have over fed her. Let her rest for about an hour. Since birds store food in their crops, it fills up pretty fast. After it is digested it moves down to the stomach. I have never heard of a tiel or any bird suffer from bloat.

Baby birds make sort of hissing or gasping sounds. This is normal. How do you know it is air and not food? Baby birds crops can't hold much food. You need to let her rest. How are you feeding her? If the crop is large, she has had enough to eat. If you are concerned contact your vet and ask them to show you how to properly feed your baby. may I ask why you are feeding her? Where is her mother and father? Baby birds shouldn't be hand fed until they are at least two weeks, and then you can start hand feeding and taming. You should really contact your vet.

I hope she is ok and let me know what happens.