We have ten hens in a coop with four nest boxes...same size each.. but two on top of the other two. The hens hate to lay in any nest other than the bottom left nest box. They will stand in line till one hen leaves to get to that box. Last Tuesday, one of the hens was sitting in the nest box when others had gone to roost...next morning still there. She moved, however, and I could see that she was not sitting on any eggs. I put several under her...including blue eggs. She was on the nest all day and night. On Wednesday morning, she was there when we fed but when I checked on her later, she had another hen with her in the same box. The other hen laid her egg and eventually left. The broody hen was on the nest until today. The other hen was sitting on the nest and the broody hen was in the top right box. When the other hen left, the broody hen got back on the lower left nest and all seemed well. However, in the top right box there were two eggs...one of which was blue and there are NO blue layers in the coop. I had put the blue egg under her in the bottom left box! Two questions: 1) How in the world did that hen move that blue egg to that upper box?? She had to jump on the roost in front of the box to even get in that box. 2) Will the eggs have a chance if she lets "girlfriend" egg-sit? Will the eggs stay the right temp to hatch? What an interesting group of individuals these chickens are!