David Hare-Scott wrote:
....
No, you are over generalising. It depends on what the horses have been
eating. There are plenty of situations where horses on either hard feed or
pasture do not eat viable seeds. If you don't know then test some first and
if it sprouts then hot compost it. There are other reasons why you might
want to know the provenance of your manure as well, such as the possibility
of contamination.

from my reading of the OPs post i'm thinking they
knew it had seeds in it but was just mistaken that
seeds/sprouts would survive the winter.


songbird