I noticed something very early on in the soils development. Sheep manure requires a lot of moisture to activate it. Horse manure attracts a lot of moisture – if it doesn’t already have it.
I have come to the conclusion that both are great together for various reasons.
The sheep manure seemed to attract more of the compost-type worms. Those that had been introduced to the garden through pot plants and a few random scatterings from a worm farm at the previous house. The horse manure was a little more gentle in strength and was a perfect home for the native earthworms to hang around in during the warmer weather and then kept them moist through the winter, but with plenty of drainage. The horse manure really was the way to go for the sandy soil though as it built a layer of moisture catching earth, gave the earthworms somewhere to hang out and begin to break it down and gave them access to the sheep manure which had a hard time breaking down in the sand on its own, despite watering. The horse manure kept the moisture constant.