Sacalait got well broken down basically composted manure. I will add that if you're putting in old stable bedding material, you've scored a bonus. Contained in this will be urine, which is rich in potassium, nitrogen and sulphur, so you may not need to correct for any deficiencies. However, if the stable material is sawdust or wood shavings, these use large amounts of nitrogen in breaking down and will nearly always create a deficiency. This being the case, add a rich nitrogen-based fertilizer as you go.
Fresh horse manure will sour your land and contains weed seeds which won't be sterilised unless composted at a high heat... don't use it without adding lime and nitrogen. All barnyard manure is highly acid, add lime to it in the compost heap and dogsh*t is useless because dogs are carnivorous. Fresh manure from herbivores has to be composted before using.
Chicken manure is the best value for money and needs little nitrogen..
Allie