Hi! We have 4 chicks...barred rock, black Asian, ISA Brown, and a California white. They’re approaching 2 weeks old. We never have had chickens before. We purchased a prefabricated coop, got it halfway putt together and decided the quality was junk, and too small. We decided to build a coop, which would be much sturdier and this design fits our very small backyard well. I do have a couple of question. 1) Will it be an adequate size for 4 hens? (I hope they’re all hens!) I hope to let them free range in the yard if I can clip their wings so they don’t go over our 4 foot fence. They might need to be in the coop for a week straight if we’re out of town, we’ll have someone check food and water daily. 2) We live in Kansas City, MO and our winters can get very cold. Definitely single digits, and occasionally below zero. The coop’s design has an opening in the floor of the coop where the chickens can freely go from their run up to the coop. The plans don’t show a door on this opening. Would it be too cold in the winter with this open? We don’t plan on using any supplemental heat. We’d like to start building this weekend and wondered if we needed to make any winterization adjustments. The window is screen, and some who have previously built this plan said they put plexiglass over the screen in the winter with five 1/2” vent holes drilled through it. A sketch of the coop is attached. I would be very grateful for any advise!!! Thanks!