Our fence is 8in diameter pressure treated posts with tapered ends so that they could be pounded directly with a post pounder. We put it all in ourselves 13 years ago. There are more posts than I can remember as we have almost 15 acres fenced with post & rail. The rest is posts and electrobraid (a crap product - but that's another tale) We have had to replace about 6 posts. 2 from bobcat "incidents", 2 that split from what I assume are weather conditions getting into an existing split/knot in the wood, 2 posts broke of horizontally at ground level. I have no idea how those 2 broke.
There are two types of pressure treated, regular which can contain arsenic and other poisons and "animal safe" I do not know how they treat the animal safe type. We have just regular.
If you can get them and let them sit for a long as possible to continue drying, that would be good. Our posts didn't seem to shrink noticeably, but some of the rails have shrunk an inch or more each. Posted via Mobile Device