I use a plastic water trough which is pegged down, this is filled manually from an IBC which is on the other side of the fence. It is a bit of a pain to keep clean though, I like the idea of nipple drinkers so must look into it. Got 6 weeks to get organised before my next batch of wearers arrive, going to be 5 saddle backs this time as my supplier of osb's hasn't bred any this year.