My 4 chickens just started laying about a month ago. My black sex link has been laying almost daily and is 27 weeks old. She started an odd behavior 3 days ago and I am at a loss as to what is going on. When she is ready to go in and lay an egg, she gets very agitated off and on for about 30 minutes. She will try to fly repeatedly out of the run but the fence is too high for her to get over. Eventually, she goes in, lays the egg and returns to her normal sweet behavior. Any ideas what is causing this behavior?