5 week chicks, mystery breeds!

[MapleKehDucks]

I purchased some chicks at the feed store to put under a broody hen who had been sitting for over 2 months. My main goal was to help Darla get off the nest, so I wasn't super picky about the breed of chicks (although I knew which breeds I definitely did not want). The store I went to had received some chicks that were UNLABELED and so they were discounted because they were mystery chicks! I got 1 labeled leghorn and took a gamble with 3 mystery chicks. I'm fairly certain I've got one chocolate orpington, but I have two that I just CANNOT FIGURE OUT. These two were in the same bin, one was very light gray, the other was a darker gray. They have yellow beaks, and slate legs. Heads are without tufts, no beards forming, and legs are without feathers. The darker gray one has a comb that is redder than the other (diff breed or diff gender?)... I'll take all guesses! (pics 1-2 are the darker gray chick, pics 3-4 are the lighter gray chick).

 

[Rhodebar Lover]

I honestly think they might be Blue Jersey Giants. Hoover’s carries them and they seem to be large, have yellow skin, and slow to mature

 

[MapleKehDucks]

I honestly think they might be Blue Jersey Giants. Hoover’s carries them and they seem to be large, have yellow skin, and slow to mature

They are the same size as my leghorn and "orpington" chicks right now. I understand Jersey Giants are much larger birds (when full grown). At what age do they usually become bigger?

 

[MapleKehDucks]

The lady at the store was pretty confident they were Cochins... but their legs have zero feathers... so that means not a Cochin, right?