We have 15 chickens we desperately need to build a coop for. How big should our coop be? They are only 6 weeks now, but will be full size Buff Orpington Chickens.
Any help will be great. TIA
68 sq. feet. I allow 4 sq ft per bird, and 4 sq ft each for food and waterer. I'd also put on EXTERIOR nesting boxes, 1 per every 4 birds. so you can get away with a coop 8x8 square. Ours is 6x8 with 6 birds / exterior boxes. It's in our page(s)
8x8 will do you fine if you have a run as well ... but build bigger if you can because you WILL want more chickens.
The general rule of thumb is 4 square feet per bird inside and 10 square feet of room outside. That is a MIN. and bigger is always better, and keep in mind if you will ever want to add more having extra space is nice for that.
Mr. Peepers :
Storey's Guide to Raising Chickens says 4 sq. ft. per bird, but experts do differ.
The Virginia Cooperative Extension says 1.5 to 2 sq. ft. per laying hen. Go here to see everything they have to say. It's a good site with plenty of info.
A lot of the information on the extension sites is for commercial operations where they clip the beaks, keep them inside, and have 10,000 laying hens in one coop. Most of us here try to give them enough room so extraordinary measures are not necessary to keep them from harming one another. I get a lot of good information from the extension sites but I don't rely on them for space information.
The Virginia site is also on my list of very good extension sites. I'll include a few others. My personal favorites are Texas A&M and Mississippi State.
NC State Site
Mississippi State site
My chickens have a little over 8 square feet of coop space per bird with a large run attached. I would not want it any smaller. They are comfortable, it doesn't get dirty as fast as a smaller space, and I have never had any pecking issues. Everybody has plenty of room to avoid that nasty boss hen. But I am one of those that heartily disagree's with the minimum standards.
I visited a local state park this week that has a large flock of 50 chickens. I couldn't see inside the coop, but it was huge. From my calculations, that had 20-25 sq feet of run per chicken and these chickens looked very calm and relaxed. The coop was like 10-15 sq feet per chicken...way oversized.
My chickens are enjoying 7 sq. feet per chicken inside the coop and 15 sq. feet per chicken in the run with access to both during the day along with some supervised free range a few times a week. These numbers will increase when I rehome my rooster next weekend, leaving only three pullets
Oversized is preferred (or double the minimums of 4sq. feet in the coop and 10sq. feet in the run) in my book. It makes chicken poo management easier too.
As big as you can bring yourself to build it. HOnest.
That way, if you decide you want more chickens (and most people do seem to... ) you will have some flexibility; and in the meantime your chickens will be happier and your management tasks will be easier.
There is no such thing as too large a coop
Good luck, have fun,