Don't know why your quote didn't quote. Re: 2 x 4 at top of HC, those openings will be quite the invite to rats and weasels. Especially weasels. They can wipe out an entire flock in a single night just for the sport of it. A small weasel can squeeze through an opening the size of a quarter.
yeah, the weasels worry me. I don't know if they would climb up the sides of the hoop coop, but maybe. I kept thinking the fencing wasn't the best idea, but it seemed everyone I was checking with was using it and not having a problem. However, some of them have coops that the flocks are safely locked up in at night.
Ok, I moved the brooder to the ground, and I am leaving one of the tarps on the south side rolled up about 2 1/2 feet up from the ground for better air circulation. At 4 am when I leave for work, it should be about 48 degrees, and I will uncover the brooder (it has a tarp on it for the night, and a sheet on the open end for wind). Only going to be 70 tomorrow, and I will turn the mhp down to the middle setting. I counted wrong, they will be 6 days old tomorrow!