Ok first of all I'm not saying that reptile nutritional and human nutritional needs are they same BUT they are similar in that rodents don't always contain every possible nutrient that a snake could possibly need. Maybe the rodents do in the wild but that is because they feed on whatever they need or want. Rodents breed in captivity and fed a premade, man made food could be lacking in some way. This fact is proven by the while "what should I feed my rodents?" arguement which pops up on here pretty regularly. It's possible that whatever you happen to be feeding your rodents isn't "perfect" and may lack a nutrient or mineral of some type. Also it is a proven fact that frozen foods lose nutrition and minerals over time. So it's possible that an animal fed frozen thawed feeders could develop a deficiency. Is it a life threatening deficiency? No probably not. But were not in this to simply keep our snakes alive now are we? We want them to be in optimal health at all times. Is it proven that vitamins help? Is it proven that it doesn't? NO. To say it a waste of money is a little narrow minded. Who knows maybe a female that is supplemented with vitamin throughout the breeding and laying proves will lay a larger or healthier clutch. Who knows maybe a hatchling will have a better, faster growth rate. Wh knows maybe an I'll or injured snake maybe recover or heal faster.
To say it's a waste of money quite frankly is something you don't know for a fact. You're GUESSING it's useless just like I'm GUESSING it will be beneficial.
I for one want my animals to be as healthy as humanly possible while in my care and vitamins have been proven to help almost every species of pet and livestock that is kept in captivity and at a rate of a couple cents per feeding why not offer every possible advantage to your snakes that you
Possibly can?