Quite interested in this thread. I picked up a rig a week ago as a foster and he has been on supercalm. Ive never had the need to feed calmers in the past. I actually just finished his supercalm in his dinner tonight after gradually reducing the amount he got so as off tomorrow he will no longer be getting it. It will be interesting to see if i see any difference in his behaviour but then i wouldnt really know as he has only been with me for a week and hasnt properly settled yet.
Depends what you are using. For most of the over the counter ones, I would say only if it relaxes the owner to know the horse is on a calmer. Transference placebo?
I use Magic on my 5 year old gelding beginning of spring, he goes loopy then and it helps me handle him better. He's off it the rest of the year though
I put my mare on one a couple of years ago and I thought it worked, I had someone else riding her as well who had been off due to injury (not caused by my mare) and when she came back the first thing she said "what have you done to her, she's a pleasure to ride now!
Before the calmer it was like riding an unexploded bomb!