[cypher]

I really don't like to second guess vets but of all they've said I do find the flea treatment the strangest, I know dogs & cats can react badly to it as it is potentially quite toxic so personally I wouldn't want to be putting that on a ham without very good reason.
Infections & the stress that goes with them can impact the immune system & then the mites that all hams have can get out of control & need treatment so I don't know if maybe that's what they're referring to? Even so I would never use mite treatment without knowing for sure that the mites were causing a problem which your ham doesn't appear to have, if you want to help the immune system & help her cope with the general stress of illness, vet trips etc the only thing really is to maintain a good diet, give probiotics (for small animals) & sometimes a little nutritional yeast (sold as a supplement for humans) can help too.