Hi, we just got 3 baby chicks before Easter and will be getting two laying hens as soon as we can get/build a coop for them. So we'll have 5 total pullets soon. My question is, can I get a used large dog house, and use it for a coop? I found one that was for a Rottweiler, very cheap. Or do the chickens need more space? My husband would build a covered run onto it. Thanks!