My birds go into their coops for food because I keep the feed in hanging feeders in the coops so it doesn't get wet when it rains. All of my pens/runs are 60 ft. by approximately 20 ft. They spend the majority of their time in their pens. Some of my coops may be a bit crowed but there is enough roost space for all plus a little. It depends on the breeds, bantams take up less space than large fowl. There are no set rules and each person has to decide for themselves if their room is adequate. Also where you live and the climate is a big factor. I'm in North Central Florida. We do get some cold weather but it usually lasts a few days and then warms up some. I have had 18ºF in the winter where my bird baths have frozen solid, but that is unusual. I do have shade/rain tables in each pen for the birds to get under. They would rather spend their time in the heat and rain under the tables than in the coops (which is in a previous post). (https://www.backyardchickens.com/th...sq-ft-per-chicken-rule.1282922/#post-20711480) It might be an option for those in snow country for their birds to have a place where they can get out of the snow.