I'm new to the world of chickens and have 6 adorable 1 month old chicks. My question, given the fact that I'm in north Jersey is what is the best age for them to go in the coop? I've read anywhere from 4 wks. to 8 wks. There must be some optimal age when they're not too young or too old! I've insulated the inside and covered that with two thicknesses of heavy duty construction plastic. Next question -Will this plastic work or will they eat it? Please don't tell me that!