I’ve always had small horses. Back in my boarding days, I boarded anywhere from one to five, at places ranging from pasture to partial self care to full board.
I boarded for several years at a place where stall, turnout, and hay (grown on-site) was included; the boarder provided concentrate rations, supplements, and bedding. By the time I worked up to four and then, eventually five, I’d already boarded there for years. The BO (who lived on-site) voluntarily offered the additional stall I required for free – so I ended up with a discount that was 20-25% off what would have been the total bill for four or five separate people.
By this time, I had a reputation as a trouble-free boarder who paid in full on the first, with non-destructive, well-mannered horses (especially important because her children fed and turned-out). I kept a lot of my tack and equipment in my trailer, so didn’t require as much space in the tack and feed room as multiple people would. Didn’t require as much parking space as multiple trailers would have, either. I helped bring in hay from the fields and stack it in the hay barn, I never left a mess in the barn aisles, I’d volunteer to clean out the water troughs, etc.
It was a whole lot less trouble for her to have me as a single boarder than to deal with several people. My discount was for that reason, not due to the size of my horses.