I used a lot last year. 6 or 7 loads at ~ 18-20 tons each best I remember details. I continue to see terrific benefits from it. The differences between the fields with litter vs without is notable. I will be putting more out every fall. We were putting anywhere from 1-3 tons per acre. Next round I will use at least 3 tons per acre.
Biggest challenge is spreading it. We 'poached ' a lime cart which works but is not best. The coop does not particularly like us spreading litter with their cart. I would buy a spreader if I cold find one at the right price.