I'm not really sure what options you would have other than wood or concrete blocks. A picture or description of what you have might help. I'm not trying to be difficult, but raising something off the ground is going to require some sort of something to raise it up with, that's usually going to be wood or concrete blocks. I suppose one might be able to figure out a way to use large rocks. If it's a really small coop you might be able to make legs out of PVC pipe for it or iron pipe. Stacking up old car tires maybe? That's what I can think of.