We use a mobile coop/tractor that I move every week to 3 weeks depending on time of year and our number of birds, it changes due to our egg layers/meat birds. If you don't provide a place for dusting they will create it for you, this can be good. After moving them you have a patch of bare soil where you can dump a load of compost in and plant whatever you like.
At our new place the pasture sucks so I have a 5 gallon bucket full of my own seed mix that I throw down first, then cover with the compost, slowly the patches spread and you improve your forage. Otherwise look at using a kiddie pool or a large plastic concrete mixing tub( what I prefer as they have better UV protection), fill with whatever you like, I usually screen local soil through 1/2" hardware cloth and throw that in , along with some DE. I keep this under the tractor where it stays dry year round!