If it's from mucked stalls it'll need six months or more to compost due to the high content of urine.
Horses piss a lot and it's tempting to grab because they have straw as well but the quickest way to kill a good jar of spawn is some hot poo.
The nitrogen content is high!
I never had any luck with bagged poo because of this problem.
All I'm saying is be careful with a mucked stall unless it's been composted well!
Edited by roc, 22 January 2019 - 02:01 PM.