They're kind of bugged at the moment, so sometimes they work and sometimes they don't. Just wait it out a bit before they work, or you can ask someone for a refund of 10 grass.
Its a little bit screwy. If you would like a refund of grass just ask me in game or send me a message on the forums.
Another point on this, if you're not already aware: You can ask a Skygod, donor 250 or donor 400, to spawn you some sheep using /spawnmob. In addition to this, you could also buy a spawner and request for it to be changed to spawn sheep. These are just some ways around using a spawn egg on your island for sheep, considering that they don't work or are currently glitchy.
Locking thread due to inactivity and for the fact it is resolved. If you disagree with this, just report this post and the staff will reconsider. Thanks, The Staff