So much of what you pay depends on what the barn help is required to or capable of doing. My young adult grandson spent a summer helping out on a farm. He could do a lot with the horses - standing wraps, polos, blankets, tack up for lunging, lunge, tack up for someone to ride, groom, clean tack, meet the farrier and vet, minor wound care such as cold hose, scrub, re-wrap, etc. He knew how to look over a horse and check for illness, lameness, knew about foaling and breeding. He could also take the truck and hook up the six horse goose neck trailer, drive to the gas station, fuel up, check all the tire pressure, fluid levels, change the INSIDE tire on a dually, change the oil. He knew how to back up the rig, could load horses safely, drive safely, Plus he could run the farm tractor, and change from the bush hog to the scraper blade to the hay spike for round bales. He could tell good hay from junk, repair fences, dig a post hold and set and brace a corner post, etc. He was never a very good rider, he was a kid who really loved horses and outdoor work. He got this from his mom who was a good rider and horsewoman, and his dad who knew how to do all sorts of things around the farm.
He took home $10 an hour, after income tax and Social Security, plus living quarters and all his utilities paid for him, and they fed him most of his meals. This was in a not very prosperous area of NC about four years ago. Their regular guy went back to his home in South America for the summer, I am not sure what they paid him.
You might want to ask around, but again, so much depends on what you want the person to do, and how dependable they are. You can teach a person to put on standing wraps but you can't teach them to be reliable and show up on time.
I'd offer minimum wage or a tiny bit more. You might find you are better with a couple of people who rotate on various days, that way if one is sick/vacation, the other can do more. The 'turnout' part ups the ante, as you are asking someone to handle horses. Many rather uneducated people are really hunting for jobs right now, but finding a dependable person to handle your horses is not as easy as you might think. How many hours a day would the job entail? How far would the average person have to travel to do the job? How many horses, two or ten? How difficult is turnout? Do they have to lead the horses in and out one at a time? Or is there an easy way to just open one barn door to a run, then open the stall doors. And how difficult is it to water in very cold weather, is this an early morning job? All those might nudge up the amount you pay. Good luck.
$10 per hour, after taxes. The more part-time it is, the more it will cost you because you have to make it enough money to make it worth someone's time to drive to your farm, and work the hours you want around another job.
How part time? if you are talking 2 hrs/day then you'll probably have to pay more than someone getting 6 hrs/day.. just to make it worth driving out. probably 15.00/hr i'd think. And definetely not a 1099 situation I'd think. You'd be the employer, they aren't an independant contractor.
The Trainer could be an employee or a IC.. depends on the role at the barn.