" I'm looking at 4x4 field fencing for permanent fencing. I'm thinking this will keep in sheep/AGH and coyotes out. " I would not be comfortable counting on 4"x4" fencing to keep coyotes out. I watched a neighbor dog, about the size of a coyote, go through a fence that size. He had to work at it and it took a few minutes but it was possible. We use 2"x4" field fencing with barbed wire on top, for coyotes and neighborhood dogs. We lost two milking does (goats) and two goat kids to dogs before we put the barbed wire on top. Saw one dog climb the fence (before the barbed wire was installed in loops, like you might see in prison pictures) on his way out after taking the tail off of one of our next batch of does.