check out and google worm farming as they use and breed blue nose worms for landfilled sites
they often use horse manure
also check out large fruit farmers as they to use manure to spread under the trees as it helps to keep moisture in to feed the plants during the winter months
I have a 4 yd and a 3 yd dumpster, and they're emptied once a week. I bed with shavings, and in the summer there aren't many shavings in there, but in the winter, when the horses are in at night, I go through a lot more shavings. I can dump yard clippings in the dumpsters, too, but no trash. I pay $100/month to have this service.
I am in a similar situation with 2 horses and not much land right now. They are outside 24/7. I put an ad in my county's freecycle yahoo group and I also contacted the local Master Gardeners. We figured out a system that is working great. I have a group of people that come by and pick up the poop weekly. They furnish their own big plastic buckets and I fill them up and set them behind my shop. The buckets have their names on them. I use a muck cart and I pick up the poop daily. I fill about 8 or 9 buckets a week. This arrangement solved my manure disposal problem. You can buy the big buckets for $6-7 each. I keep 4 or 5 buckets of my own in case the others get filled up too quick.
I called a few nursery's they weren't interested. For those who use a dumpster... Did you tell them what you were putting in it? We have to haul our household trash to the dump so maybe I could kill two birds with one stone!!
I also have a small property and have been lucky to find some big gardening businesses that are willing twice a year to pick up my manure pile for their compost pile, I also found a guy that needed fill for his property and will come get it. Canvass the bigger companies and ask them if for a couple hundred bucks if they would come get it.I do not have a tractor w/ a loader so I also bought a pull behind manure spreader that I just put the manure in (wet bedding goes in my wheelbarrow for the pile) and spread it on the field that the horses have just rotated off of. I find composting difficult w/o a tractor.
i also do the composting and then posting on FreeCylce and Craigslist - you would be amazed how fast that pile disappears! at my other larger facility i even had someone bring their own tractor and dump truck to haul it all away!
the key is to keep it moist and turned so it composts quickly.
I have a 2 cubic yard dumpster for the manure from my three horses plus the household garbage.
I clean stalls and pick up all the manure from the dry lot in a wheelbarrow, then take the wheelbarrow over to the dumpster and use the manure fork to heave ho it into the dumpster. Yes, it's handling the manure twice, but I always figure that lifting those heavy loads of manure is a good upper body exercise.
Heave ho, I'm afraid. But I've learned not to fill the manure tubs full, so they don't get too heavy. Great for the arms, though. I've got muscles...but I've also got barn help, so I don't have to do it every day. When I did, I developed tennis elbow, and that was no fun.
If I lost my helpers I'd use my tractor to dump the manure. I have a friend who has a ramp that she can wheel her manure up and dump it. Another friend has her dumpster placed down a little driveway, so she just dumps her wheelbarrow down into the dumpster.
we post ads on craigslist for it and put signs out at the road, and it all gets taken away - and we usually have anywhere from 13 to 16 horses here at any given time. Stalls and paddocks get picked daily/weekly, so we have a LOT of manure.
I'm ready for spring to get here so we can get the large pile that's accumulated over the winter out of here. :/