So one of my hens which i thought originally was maturing the fastest turned out to be the slowest. The last couple of days she been resting a lot. I let them out in the yard today the other 5 hens are running around eating everything and doing there normal routine, but this on just came out and sat down and ate some grass around her. Her comb seems to have stopped growing, almost like smaller then it used to be. I upload two photos of the "sick" one and two photos of the other both are the same age. Any ideas?