For the winter, I moved my flock into a smaller room in the barn with a wood stove in it. Because I lost many chicks to rats, possums, raccoons, etc. I tried to go overboard on security. I have a grated door covered in a tarp with a wooden board on one side and a metal panel on the other blocking one entrance, a screen door with the bottom blocked off by a thick plastic panel with the rest sealed off. The door I use is another screen door with a board underneath covering a 6 inch gap. There is also a plastic barrier preventing any pests to crawl up and over the board. There are no holes in the roof or any along the ground (that I could see...) The only forseeable problem is a rat crawling through the pipe used to drain floodwater from that room, but it would have to crawl about 100 feet. The floor is covered in about 6 inches of mesh hay too. Mice are not a problem, in fact I welcome any mice that show up because they are cute and can co-exist with my chickens. Rats and other animals can't. So far I haven't seen one sign of rodents in that room, and it's been about a week. Any other tips to make sure nothing gets my precious flock during this winter? I'll keep posted on weather or not this works.