We'll be moving to an area that has a known Mountain Lion population, in fact they've been seen on our property and at our neighbors. Our first step will be lion proof enclosures, fenced in chain link from top to bottom-- completely enclosed. I worked at a wild and exotic animal rescue and that's how we kept lions, tigers, mountain lions, leopards and jaguars IN. I have no doubt it will keep them OUT. There are instructions for building an inexpensive chain link enclosure using a carport frame at the mountain lion foundation website: http://mountainlion.org/portalprotectsecureenclosures.asp
A friend of ours had the foundation help him with building a pen and after losing three pigs in one season, he's had no further losses in the two years since.
A well built chicken coop, a barn or a chain link enclosure are the first line of defense. Fencing, guard dogs, frightening devices (motion activated), removing attractants such as keeping deer away and not leaving any dog food out, are all part of a multi-pronged approach that can be very effective.