I only bought two white Bantam Silkies. They were over a week old at TSC (Tractor Supply). They are close to three months (90 days) old now. I still don't know if they are male or female. I'm hoping I have one of each. I'm pretty sure that one is a roo, but still not sure about the other. They are definitely developing a little different from each other. Hoping that is a good sign.
I'm thinking first two pictures are a rooster (same bird, just two pictures.) See the "longer" feathers at the top of its head? It also has a larger comb and larger waddles. It also has longer feathers on its body. It doesn't crow yet, nor does it seem to be dominant. But it's in a flock of 44 with two other full-sized roosters. A Bantam is about half the size of a regular-sized chicken.
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Now the next two pictures I'm hoping are a hen (female). It has a much smaller comb and smaller waddles. She is very friendly. She seems fluffier, probably because of the shorter feathers. Could I be so lucky that I got a male and a female when choosing from a straight-run batch. (Straight-run chicks are unsexed chickens. You don't really know what you are getting (male/female) until they mature. This breed cannot be sexed by color.
Let me know if you have expert advice. I posted pictures of them on Backyardchickens.com. The first person that commented today said they could both possibly be roos. Time for the waiting game.