You have been given good advice. I would like to add that they may be molting, and that is when many battery hens are sold or given away, since it can take 6 weeks to regrow their new feathers. Give them plenty of protein (20% flock raiser is good, then put them back on 16% layer when they start laying again,) and make sure they get outside to roam, and have plenty of room in their coop so they are not overcrowded.
