Part (MOST ?) of the reason to use horse manure is to keep the odor down.
If you get it from a "riding stable" (not a mere "horse barn") the chances are good that you will get it all nicely coated with pine shavings - pine shavings OVERWHELM manure odor - IMO, etc.
The uneaten hay doesn't hurt either, though some seeds survive the digestive tract, so you might get a few blades of oats and barley showing up here and there (-:
No matter, just mow it down with whatever you MEANT to grow there.
If you get it from a "riding stable" (not a mere "horse barn") the chances are good that you will get it all nicely coated with pine shavings - pine shavings OVERWHELM manure odor - IMO, etc.
The uneaten hay doesn't hurt either, though some seeds survive the digestive tract, so you might get a few blades of oats and barley showing up here and there (-:
No matter, just mow it down with whatever you MEANT to grow there.
