crop looks like a balloon

Was just palying with the babies and wondered why one of the babies crops looked bigger. Its got air in it !! Do i massage it out? What do i do?

Please, can anyone tell me what happens with my five days old cockatiel? I handfeed him from the first day because his parents abandonded him. From the second day of his life when he gets asleep he looks like the photo. He can't wake up alone. I have to make gentle massage for about a quarter...