we spread ours on our paddocks every six months and then leave those paddocks for another 6 months. My contractor will take it but he charges me £70 to remove 2 muck heaps and it is such good stuff we might as well use it as fertiliser is now so expensive. it has to be well rotted and it does depend on the type of bedding you use. Would not recommend it for straw or shavings as 6 months is not long enough for it to break down. we use woody pet bedding and have a cocktail of muck heap worms in it so it breaks down really fast.
We do advertise it on Freecycle website and have loads of people collect it which may be an option.
Try allotments and or nurseries they may be happy to take it off your hands if you can't reuse it. But I would always say try and use it your self as it will save you a fortune