help with coop and run design please (new drawing added)

That sounds wonderful. I would not start with too many chicks at once, it might be overwhelming. Although I love the idea of sooooo much space. RIR can be a bit fiesty so not too many in a space works well. My Mom had them and did not have enough space. They picked each other terrible. She got rid of a bunch and things were much better. As long as there is lots of ventilation on the sides and front of the coop things should be fine. You could even break the area inside down and make a nursery -grow-out area that could be seen by your bigger hens but devided off with wire for the future addition of new chicks. I have a space and it really helps with intergration issues later on. Oh the run can be devided off too. Then the new ones could get outside some.
WELCOME TO BYC Gloria Jean

 

Twenty sounds great- you have to be able to name them all and tell them apart

 

Could you describe your location/climate, please? I think you will get more detailed suggestions if you do.

Also, some members have gone away from bare metal roofs because of condensation and since it's early in your planning you can consider that. Unless you plan to insulate and sheathe it, in which case you can avoid that problem.

It's sounds like you're starting with a good space, and new ground is always a bonus since it should be disease free. Be sure there are no vents from the garage where car exhaust could enter the coop.

 

I hear lots of folks say they just have bare ground with sand on it, and they use diatomaceous earth (DE) to keep the flies and moisture under control. Then they just rake the sand.

Don't bother trying to grow grass in there. Chickens are better than freeway traffic for grass destruction. But sand will keep the run from turning into a mudbath.

ALWAYS start with lots of space!!! You can NEVER have too much space!!! Even if you PLAN on having only six or seven, you ALWAYS wind up with more!

Especially if you visit BYC often enough. Chickens are contagious, doncha know.

 

All good suggestions so far! I'd agree that 20 isn't too many except that if you start with 20, then find some others that you just 'can't live without' you might not be able to get them if you decide that's your limit.

I agree with having a seperate area for new chicks or for a brooder if you have hens go broody and want them to hatch a clutch. I know a lot of people tell you that RIRs don't go broody, but several of mine did and were great mommas, so it's not a sure thing either way.

 

250 square feet... you could do 50 or 60 easily.

Wow...we all WISH we had that kind of room.