Horse manure management need not be daunting nor unmanageable.  I am going to share the methods I use that work very well at my altitude of 3700 feet in the Cariboo  of BC. Frost is a given at least once a month.:)  I am not in an area where I have to be concerned with leach-ate or any farm runoff  that could end up in a waterway.

 

Method 1
Spread 1 foot of horse poop and any other stuff you want to compost. I usually make a row as wide as the tractor bucket and as long as I think I need to. Water to totally soak material, inoculate with bacteria ( you can spray it on with a garden hose using a miracle grow fertilizer container or get a venturi that hooks to your tap and your hose hooks to the venturi.) Spread another layer 8 – 12 inches deep, repeat soaking and inoculating. Keep up this process until you have your row 4 feet deep. Finish by soaking and inoculating the top of your row. I cover mine with used shavings from the chicken coop to keep the moisture in. You can cover with anything… just remember to keep it moist…rain is good. My row is about 80 feet long and I use about 4  1000 ml TB in the miracle grow feeder that hooks to your garden hose.
Method 2
Gardening: If I were to want to plant say raspberries. Pick your spot. If you have cardboard you want to get rid of or personal papers, or newspapers lay them down over top of the vegetation where you want to plant your raspberries. Add a layer of horse poop 8 inches thick… water and inoculate as above. Continue this process until you have 32 inches of horse poop. Soak well, add 6 inches of shavings… stick raspberry canes into the top of the shavings ensuring the canes are pushed in to a depth of 8 inches. Water well. Continue to water and add bacteria through out the season as you would to keep the canes alive. By fall you will have your raspberry bed. No tilling , no weeds to kill, simple fast and easy. If my row for the raspberries was 20 feet long by 3-4 feet wide I would use 1  1000 ml TB
Method 3
To improve your pasture or lawn:  Pick an area of your pasture you would like to improve. Temp fence it off. All winter you can dump your horse poop and uneaten hay in this area.  Harrow in spring. You want to have about 3-4 inches of raw material in depth prior to harrowing. When the material is all broken apart and loose if you wish to seed now is the time before your last harrow. Water really well and inoculate with bacteria. I often have all my harrowing done early spring and as soon as I have a pouring rain day I am out there on my quad with the spray tank inoculating the area with bacteria. ( 50 liters of extended TB per acre)
Method 4
This is an example of how you would have to manage the composting of your horse manure in areas where leach-ate is a concern.
Year 1:  Layer and fill bin one with horse manure/straw/hay/shavings etc using the same methodology: soak with water and inoculate with bacteria as discussed above. Keep moist. Keep covered as shown.
If odours are a concern, place 6 inch PVC pipes with 1 inch holes drilled in them into your manure pile to facilitate the survival of oxygen dependent bacterias
Year 2: Fill Bin 2 and continue with the same methodology of soak and inoculate. Keep moist. Keep covered.
Year 3: In year 3 if your manure in bin 1 is not fully composted you would transfer it to bin 3 making sure to soak and inoculate and use bin one for your new manure. Transferring it will turn the compost and help speed up the process.
If the manure is fully composted, you can now use it for what ever your heart desires. This will leave you with the option of using bin 3 or bin 1 for your horse poop.
How I saddle Gemini in the horse trailer with the saddle hoist
Debbie Hughes Confidence and De-Spooking Clinic 100 Mile House, April 28 & 29, 2012