I have 3 to 4 month Maran pullets. 6 of them. They have had a penned in yard a week and they were hatched by hens in a penned in yard. They lay down on the floor of their 10 X 14 barn most of the day and only come out to eat grass a few times a day. Is this normal? I feed them laying mash and I think I read not to? They may have mites and I will treat them with powder for that tonight. They seem healthy. Any thoughts?