You need atleast 1 sheep to hit, and you can only summon 1 sheep every 12 hours with 1 character. So at least 1 per day. (If you lure a wolf or something on you)
I ment, how many spellwands does it take to summon a sheep. Is it 100% you get a sheep?
EDIT:
Saw on Wikia its about 75% per wand, so thats nice
Found 9 wands in the market, so hopefully this will help me do a few days