They have a little less health if you dont have "Endurance trainning" and a little more armor if you have "Thick hide". Mine gets to 4100+ health (with "Great Stamina" rank 7 or 8) and 5000+ armor (with no "Natural Armor" the pig is not "Best friend yet"), I got both pet life and armor enhancement talents maxed. And ho, by the way, the little brat refuses to teach me charge 6, anyone get the same problem?

(ps : http://www.goodintentionsguild.info/hunters.html is good for anyone interested in hunter pets)