I have a 10 x 12 enclosed shed that housed rabbits and chickens Salatin/Raken style and the litter is at least a foot deep to a couple feet in spots. It is in a suburban area and unfortunately I don't have anywhere to put it and my mother wants her shed emptied. It is just north of Cincinnati in West Chester, Ohio.
The litter is composed of pine wood shavings from Tractor Supply, and rabbit and chicken manure. And of course random rabbit and chicken feed strewn about in the layers.
It has been sitting undisturbed for a couple of years so it should be good and mellow. You would need to get it out of the shed and haul it out yourself.
That sounds like a LOT of material. I'll be in Cincinnati next week, and I'd possibly be interested in collecting some, but not all. Daughter has a very small lot in West Price Hill neighborhood, and I had plans to help her amend about 100 square feet of garden.