I have a 3 week old Cochin chick that doesn't seem to be growing. It also occasionally gasps and shakes its head. Of 22 chicks of various breeds, it's the only one. They are fed fermented, unmedicated meatbird feed and water with acv. I have also been treating the chick with vetrx for about a week but no change. I'm not sure what to do for the bb. It's a standard size bird, but it's barely bigger than the oegb of the same age. If anybody has any suggestions, please help.