This is probably a stupid question, but can you have a "runt" chick? I bought 2 australorp chicks from TSC and one is just so scraggly looking. It was noticably smaller when I brought them home and it just has not been developing like the other one. They are 4 weeks old now and the one chick is pretty much fully feathered, while the other one has these weird patches of feathers. I read that roos can be slower to feather out (they're supposed to be sexed pullets but I know how that goes).
But it's not just the fact that it's slower, it's the way it's feathers are coming in. It just looks so odd. So I thought maybe a delayed chick?