Hi everyone. I'm a soon to be new chicken mama, and my husband and I are currently working on the coop. We live in Michigan, near Ann Arbor - the weather can get quite cold in the winter... My question is - Do we need to build insulation into the coop, or is a heat lamp sufficient? Most of the coops I've seen online are not insulated, but perhaps they are southern-owned coops? Thanks for helping a newbie!