Hi,
I would suggest that you get your bird to an Avian vet as soon as possible. If the rear end is swollen or extended it could have a blocked chloaca and left untreated will result in the death of your baby.
The fact that it isn't holding its head up is not a good sign either, if this is conistent.
I realize that this answer may be discouraging but it is factual in that your baby needs to be seen by a vet ASAP. Let me know what happens with the vet.
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