Image courtesy of Raw Story
Sheep are proverbial amongst the farming community for having a strong death-wish! Indeed it is even said that no Blue-faced Leicester should be sold without an accompanying spade with which to bury it …
(We should point out that it is illegal to bury dead stock mostly, but this saying pre-dates current requirements!)
The main issue for sheep is that, although they have relatively few predators once past being tiny lambs, apart from out-of-control dogs, they are quite inclined to get both diseases and parasites, particularly if intensively farmed on land which has had sheep for many years. This is of course exacerbated by their flocking instinct, so it’s a bit like primary schools as great incubators of infection. Older animals can carry a level of parasites without problems if they are otherwise healthy, and have also been observed to self medicate from suitable herbs or ivy, whenever they get the chance, and to avoid plants poisonous to them, such as bracken or ragwort.