I am interested in hearing as well - I have 3 black cochins that were given to me at a swap. (They may very well be really inbred - I don't know) One is getting really big, and fully feathered, another is smaller, and maybe 3/4 feathered, and the littlest one is half the size of the big one and only has some feathers.
There was a 4th sib who I think might have been blind as the poor thing never gained much weight and would eat voraciously if food was right there... didn't survive.
Anyway, the littlest surviving chick doesn't seem to do much but roost and sleep. S/He eats, but isn't very active. I am hoping it's just a runt and not some sign of an inborn problem. They're about 5 weeks old.
Danielle