I am new to raising chickens. I have 10 chickens, 3 BO, 3 Ameracaunas, 2 RIR and 2 Red Crosses. They are 16 weeks old. They free range in our yard part of the day. They are always eager to get out of their run. One of the RIR's is particularly friendly and loves being pet, she is usually a bit of a loner and doesn't always stay with the group. This morning she came right out to greet me and to get her morning pet, but when the rest of the group went out to explore, she returned to the coop and that is where she stayed. She doesn't seem sick. Could she be getting ready to lay? When I check on her, she is in a nesting box. Should I be worried?