Hi everyone. I am new at raising chickens and have a small flock of 4 chickens (2 white leghorns and 2 Isabrowns) - I have raised them from small chicks and they are now about 21 weeks old. 3 of the chickens have been laying eggs for about 4 weeks now. One of my Isa Brown chickens has never laid an egg yet. I am getting concerned for her health and have recently read about egg-bound chickens. When I pet her back she squats down and speads out her wings a little just like the other chickens. She seems to be healthy. Is it normal that at 21 weeks she has not yet laid an egg or is there something wrong? Thanks in advance for any help/advice! Very much appreciated.