I have my first broody hen, a bantam. She just started staying on the nest yesterday. She normally lays eggs with another bantam in the same box. Will the other hen change boxes or what and when do I start counting the 21 days til she hatches? There are two other bantam hens and a rooster in my 4 x 8 coop, will she and the chicks be ok with the others or do i have to move them when they hatch? Thanks for your advice.