Me and my friends were in some guys land really far back, and we found a huge blue barrel of cow shit, and the guy that owns the land is a big pothead, so do you think that he's growing shrooms? I don't really know what else it would be but anyway there was kind of like a hard layer on the top of it too, and we mixed it up, so how long would it take for the hard layer to grow again and the shrooms to grow?
It isn't likely that he was trying to grow them in a barrel. You could use the shit to grow shrooms with, but you are going to want to do some preparation first.
Dude, shrooms do not grow directly on the shit. It grows right next to it using the nutrients from the shit through the ground. Mixing it up didn't do a thing. The spores would have needed to be there and if they were they would have already grown.