It may seem odd for a page about pigs to follow a page about abattoirs, but the one gave rise to a thought about the other. Whilst working as a land manager where conservation was given a high priority, I undertook a fair amount of experimental work using pigs for both woodland management and bracken control.
The results were documented in a couple of papers, the first of which was (and I believe still is) published on the Grazing Animals Project website. The sequel was produced at the request of a number of keen followers of the original, and - as I keep getting asked for copies of both papers! - I am including PDF versions here. The photographs don't come across brilliantly well, as these are only light-weight files, but there should be enough detail to get the general idea.
As a slight frivolity, I am also including an article which was written for the Royal Caledonian Ball programme in 2007. Although rather less serious in nature, it does contain some interesting references to the history of pig keeping in remoter areas.
The original paper: PIGS IN BRACKEN
And the cream of the crop, PIGS IN HEATHER