Fleas are not species specific. I've had cats bring in fleas that got on hamsters, duprasi, gerbils, guinea pigs, and dogs. The fleas not only jumped on and bit them but continued to multiply months beyond when we had moved the cat to another home. One of those incidents killed my 2 dwarf hamsters because of their small size in relation to the fleas that were living on them. I suggest if the fleas are already noticed on the pigs, the infestation in the house is bad, or the fleas do not start to go away very soon to be proactive in treatment and get some advantage or revolution for the pigs. From experience small pets + fleas is very bad.