I gave you directions on how to do the poo and water. Read my post again. If they eat their own poo, they should take the poo mixed with a bit of water and they are the ones they pull from their bums but they don't always eat them. If you are unsure, just find a fresh poo (any poo) from one of your other pigs to give.
Sorry about the other link, try this one-
Probiotic Acidophilus | Nature's Bounty | Walgreens
According to GL, giving too much probiotic/acidophilus won't hurt or harm.