I have 3 young chickens of different breeds (all 24 weeks old) and one started laying eggs 4 weeks ago, another 3 weeks ago, and one acts like she's going to soon. The one that started first is a Cuckoo Maran and she stopped laying a week ago, she stopped squatting, but still sings her egg song for the other chicken that's laying. When she was laying we would get shell less eggs at least once a week but we don't even have signs of those now. She had been fighting over the nesting box but they seemed to take turns eventually. She looks healthy and acts normal to me. Any idea what could be the issue?