In my experiences, eliminating the possibility of infection is usually the first thing a good vet want's to do so I don't know why your's did not. I have never heard of a bird being "gassy", don't know if that is even possible.
He came down from Heaven unto this earth below
He came down from glory and praises untold
He came down to man fashioned in their way
He came down to rescue, He came down to save