I'll pop in here if I may? We have (ahem) 12 dogs ... cockers and labs. I'm both lucky and at a disadvantage as my OH is a gundog trainer who picks up 4/5 days a week and also trials fairly intensively.
I'm comparatively new to it as we were both horse based with some dogs, but as he's lost...
And if you're selling to the States nowadays you have to have a 100% perfect full set of xrays for their vets to examine. Otherwise they'll walk.
I've sold a couple to America. It's a very demanding very specific market.
I think Dr David Marlin has done some investigation into their efficacy.
I suspect scientifically speaking, there's no action but if they work for the horse, then they work.
Shropshire. Got everything you want
Friends of mine run a livery yard with arenas, farm ride, year round turnout - all within decent travelling time of competitions and trainers. £35/ week diy.