I purchased four chickens in May. The sexton started laying eggs in September. The Rhode Island Red, Easter Egg-er, and Rock have never laid eggs. They appear to be happy normal chickens, ruining around the yard, eating, and socializing. They are not brooding or seem to be egg bound. Several weeks ago I kept them in the run for three days, nothing. I have researched and asked a couple of experienced chicken parents, but can not find a solution.