Theres meant to be a sequence, so doing random camps isn't advised. After the pigs i would go to beat the slugs first. You'll want to breed until you pig has earthquake, then it should win. Try to get the skill that gives your pig SP, then feed it SP while it uses earthquake a few times and you should win.
Thanks... So is breeding the only way to make them stronger? just more and more offspring? Each one stronger? And does the partner matter like you mate with the strongest and the kid is stronger?
Yes, other than breeding the only other thing is to give them consumables which will raise stats. Breeding will make the offspring inherit abilities and levels, so you want to breed with the most powerful one to get strong offspring.
EDIT: nvm I found the game and Thread 
You can translate it by using google or what? you wont find more accurated translaters anywhere unless its from a english-japanese person itself... for me on google chrome it actually auto translates any site thats not in english or dutch.
