I feed all our horses daily wormer and have ever since my vet told me that once he started promoting it, he found he was ordeing far fewer colic supplies for his practice.... All of mine that are eligible are on the Preventicare program through Pfizer, so we use Strongid 2X that I get through my vet. Actually that is the easiest and cheapest way for me - I send an e-mail and it usually arrives the next day for about the same price as mail order.
My vet did check with Pfizer and he was told that the minimum dose to use for a mini was the 250 pound dose. That is what I use for most of the minis, except of course the ones that we figure weigh more than that.
Preventicare would have paid for most of Target's colic surgery in 1998 IF I HAD FILLED OUT AND SUBMITTED THE PAPERWORK THAT WAS SITTING ON MY DESK. Then he became ineligble and had another colic surgery in 2001..... Ergo, all the minis are in the program.