L&B, you are on about "Livestock" I'm on about "Game Birds" two different things under Defra.
Anyone can worry game birds, however under Defra there is no power as a farmer/keeper to shoot, or order you to leash your dog.
This is purely about not having to leagally leash your dog up espeacially this time of year, however SOME keepers expect you to do so, and believe it's "Law" to do so. Wrong.
This doesn't mean that the first pen you see, you release the dog onto it, thats a seperate isssue and anyone doing that then deserves what they get.