I have a year old Plymouth Rock hen. For the past 4 months she goes about her business, lays eggs and bosses around more docile chickens. Now she sits on eggs all day long-been going on for a week. My other chickens apparently squeeze into the Rock's bin, lays an egg and leaves. We were on a 3 day vacation and my son reported that he did not see her out with the other chickens. Bottom line: We have to reach under her and grab whatever number of eggs are there. Yesterday we pulled out 9 eggs she had been laying on. I'm guessing that she's trying to hatch the eggs??? She hasn't been out of the coop in over a week. What is going on???