Greetings, unfortunately that does look and sound like a birth defect. I had pheasants last year and one of the chicks had the same problem. The chick was hopping around, eating and drinking for weeks, but it eventualy went to the great coop in the sky. I spoke to a friend of mine who is a vet tech to see if there was anything i could do to help / save the bird but there is nothing you can do for it except hope for the best. Clearly you are a kind soul for wanting to help this bird and I wish you the best of luck.