Sorry for the late (nonexistent) reply!
I did read that thread you linked to and it was helpful! Thank you very much for that!
I definitely can see it helping with gravid females, so that gave me something else to consider, and I do think it should be used in the situation you described when not feeding whole prey items, but I'm still on the fence about using it in my situation.
I'm one of those folks that's wary of things I'm not too familiar with and the idea of overdosing him or something makes me too nervous to consider it unless it was a real dire situation.
The situation's couldn't be called "dire" at all though, he's actually improving quite a lot.
He still can't compare to my other pigs, such as his mate eating two f/t rats a week, but he's gone from not eating a thing in my care - not even being interested, to eating every other week or sometimes even back to back. I'd say he's eaten almost as much in the last month I've had him than when I first got him over half a year ago and all the months since. He still won't touch the f/t rats like I would prefer, he even turns his nose up at fresh pk, but he's interested in stunned mice now for some reason and I'm taking what I can get at the moment.
It's a start~
He's not losing any more weight now, perhaps he's even gained a whole gram or two?
I know it hasn't been long, but he does seem a wee bit more "solid".
He seems a little "happier" too for some reason, more active than he was before and that's saying something because he has always been a curious little in-your-face guy.
I can't find any explanation for it - there hasn't been any real change that I can see, so perhaps it was just a male going off feed in the summer like many people told me...? Maybe he's a weirdo and just took half a year to finally settle in to his new home...? Who knows.
I'm just glad he's turning around and hopes he stays that way!
I did get a second opinion with a different vet shortly after my original post and I liked the route the new one took more. The first one never asked about his environment or considered parasites, but Dr. Greek was very thorough. (Tests came back negative still, again I can't find a reason for his behavior.) So needless to say, I have a new main veterinarian.
His opinion on the subject of vitamins were: They probably aren't harmful, but they aren't needed for him either. He told me he wouldn't have recommended them and gave me the standard list of methods to sway a picky eater. Fortunately I haven't had to go through it again.
I still have the vitamins here just in case of... something or if anyone wants them. It seems a waste to throw them away and I'm one of those "It might come in handy someday!" type of folks so I kept the bottle.
I just never felt comfortable using them myself though.
I'm sorry all that doesn't help aid the supplement subject any one way or another though.
I haven't contributed anything, but I'd love to see a real test study on the matter. Who knows, the results might be surprising~
Thank you again for your help and also digging that thread up for me! <3