The poo they need from the healthy pigs are the ceceal poo's or in simpler terms, the poo's they eat themselves. Then take 1/2 of one of these poos, crush and mix with water and syringe feed it to the pig who needs it. This is actually the best method because it restores the actual gut flora that is missing.
If you are going to go with acidophilus, either looks for the powder or capsules instead of tablets. Something like this would work-
http://www.walgreens.com/storeproduc...18#nutri tion. It has only the probiotic they need and no other added stuff. You'd just break open a capsule and give about 1/2 a capsule once or twice per day. Read
Guinea Lynx :: Probiotics for more info on probiotics.