Had 3 Bantam hens and 1 Bantam Rooster named Chester. Then 2 roosters and 16 regular hens. I never had to keep them apart. Chickens are kind of a racial species..like sticks with like...even feather coloring sticks together though different breeds! So, a fox got our rooster Chester... and about 5 weeks after, one of the Bantam hens disappeared! BTW, all are free ranged all day, coop at night. Anyway, a month later...here she comes out from underneath our house with 9 BABIES!!! There is no way they could be Chesters, right?! Nope... they are grown now and are between regular and Bantam sized chickens.... and they lay eggs between both sizes as well. All normal..So...If the Bantam hens do not have a rooster... they need one. He will 'marry' them all, but if you dont have one... "another man will step up in his place" obviously. I didn't know what to think!!!