Well, we just got back from Lowe's and Home Depot. If you look at their shelf tags, it'll give you a pretty good idea. For a 4x7 we ended up getting 4 bags of pea gravel and 5 bags of sand. Seemed to be enough. Their run looks amazing!!!! Can't wait till they get back in there. We're also finally hanging their feeder (I say we, but I mean my bf) and I bought a suet box for them to peck at during the day. Roofing for their run will have to wait. They've got a sheet of plastic covering the wire for now. Why did I think raising chickens would be cheap? ha ha!
So is it better to use sand for on the ground of the coop then? I'm a new chicken owner and have not heard of using sand. Sounds like a good idea. Could you just scoop the "litter" then? Like you would a cat box? lol
Just do a search for sand and you'll get loads of posts about it. My coop is an open hoop type, so the ground is the floor of my coop and run at the same time. Sand works very well with this type and for a run with any other type coop. Poop pretty much just gets ground up and mixed in by the chickens scratching around. My coop doesn't really smell except when there's been a heavy rain, and only until it dries out again. Using sand inside a regular coop, I'd say you may have to poop scoop it since you probably won't have the depth of sand you would have outside for the chickens to really mix the poop in and break it down. Most folks who use sand love it.