Adopting a cage-mate -- introduce vs. quarantine?

Some shelters already have done the 3 week quarentine, and guarentee a healtly pig. Others (adopted from individuals via craglist, and some shelters) do not. If they have already quarentined, then you can introduce them and make sure they get along. If not, you just have to wing it. Im doing that right now. I adopted a male (soon to be neutered) knowing that he didn't get along with male cage mates in the past, and hoping he will like my girls when they are introduced.

You can keep the timothy pellets and hay, but add the alphapa to it. Im not 100% sure on this, but I think it would be alright for an older pig to eat too. Just not it excess.

I would never trust a shelter or humane society to quarantine. A reputable rescue, yes. Pigs from a shelter or humane society must always be put in quarantine when you first get them and should probably be treated for mites and lice.

Does the advice about treating for mites and lice apply even if the shelter doesn't have any other guinea pigs? Ours doesn't usually get many. Guess it depends where the pig came from?