Sounds like shit, lol. But shit is a fertiliser, but its called manure. Why not just go buy some fertilizers. They will prob have more nitrogen in and everything else needed and it will b more balanced.
Also it is far less hassel, and wont stink like SHIT.
Lastly do you have any sheep to collect the shit from???????? If you dont then that makes your mates idea a bit harder to pull off
About feeding, i would say leave it a few more days as the soil has fertiliser in it already so dont really need to fedd till 2-3wks but ur leaves look like they are yellowing but its hard to tell cos the pics are not great. If they are going yellow give them a weak feed, 1/2 strength will do