Hi, I am going to be building a coop for approximately 20 english orpingtons. They will have a 25'x25' run (625 sq ft = 30 sq ft per bird) that will be available to them at all times. Right now, I have 13 orpingtons in a 4'x4' coop with an attached run, and they all seem to do fine in it. That's only a little over 1 sq ft per bird (They're only nearing the point of lay so they're not full grown yet.) I've been researching the forums all afternoon, and everyone has different opinions. They may get to free range a few times a week as I rotate the birds through to get their turn in the yard. I guess what I want to know is, approximately how big does my coop need to be for approximately 20 english orpingtons that get a 25x25 run. I plan to elevate the coop off the ground so they can go under it to get out of the elements if they don't want to go inside the coop. Also, how many nesting boxes are recommended for 20 hens? I will build the coop so it is easy for me to clean out as well. On a sidenote, Is a 4' tall fence tall enough to contain english orpingtons. I'm just starting with this breed, but they look pretty hefty and appear to be mostly ground dwellers. I prefer to not cover the whole run so I can walk in it without squatting the whole time. Also, I live in Iowa. We can have all four seasons in one week, but we do go through the four seasons in a year. The chickens will use this coop year round. I appreciate any opinions. Thank you.