I have 12 Brahmas that or 22 weeks old. I know they aren't expected to lay until 26 weeks, however three days ago one hen laid one egg. It was small and round, but no eggs have been laid since. I was in the coop watching the chickens and noticed that one of the girls was trying to get in the nest box and was having trouble getting in. Do I need to modify the nest boxes due to the Brahmas being a larger breed? Could this be the reason that they aren't laying yet? Any advice?