Too much of a good thing can end up as impacted crop, and it's better to approach any experimental feeding with great care and restraint. I can just picture a crop full of dog hair, and chickens have ingested stranger things than that. You can never assume they'll eat only what's best for them. And, yes, after all I've been through with Flo, I have concluded her problem is probably in her nervous system. She would be the chicken equivalent of an obsessive/compulsive disorder in humans. Her problem is both behavioral and physiological. She's just built this way.