Just caught up with Rosemary's diary entry on this topic.
We have loads of rhodies around our land and the sheep graze freely amongst them throughout the year. I have never seen any sheep or lambs eating any of the rhodies and never been aware of any signs of poisoning in sheep or lambs. Same goes for yew trees/bushes. I had just assumed that they naturally avoided what was poisonous to them.
I should say that the sheep belong to the farmer next door and not to me, or I might have been more worried!
The area that I have earmarked for pigs has a couple of rhododendrons and yews also so I am thinking about that.
Simon