In order for you to make ANYTHING, and we're not talking about a earning living wage, we're talking about ANYHTING, over bare bones expenses, you have to do EVERYTHING yourself and you have to have a significant occupancy.
Its not like caring for your own horse and only mucking and feeding your own horses.
It's mucking DOZENS upon DOZENS of stalls two to three times a day. Follow by feeding the same amount of horses again two to three to four times a day. And that is the minimum level of effort. Because then you have to water all stalls and then pastures, and fix fences/pipes/feeders/stalls, you have to manage feed, and bedding, and you have to do the financial accounting for everything, then depending on your turnout setup, you have to move those dozen upon dozen of horses around from stalls and turnouts out to pastures grazing. And when you do that (twice a day; in and out), you have to do it in a specific order in order to manage horse personalities (who can be turned out with who, what horse CANNOT be the last one to be brought in, who HAS to go in and out with their special buddy etc.) And during this time you have to take a full minute to individually care for each horse checking for new scrapes, wounds, swelling, lameness, temp changes, feeding changes, thrush, gut sounds and general behavior again for ALL of them), and heaven forbid you need to change stall blankets for turnout blankets.
And then after everything is done you have to clean. Again.
In order to get the most money from your boarders you needs to be attentive, clean, and have a high attention to detail, because if a boarders horse goes lame or gets an abcess and you do not notify them right away, you are done.
If its the middle of winter and all of the horses are blanketed, and you are not removing those blankets every day, you can very quickly miss a horse loosing weight or have a blanket rub that gets infected, and again you are done.
Its not taking care of your horses, its taking care of other peoples horses BETTER than you take care of your own horses.
It is back breaking hard labor, that is all day-every day, you never get to be sick or go on a vacation.
Yes, you can hire people to do a lot of stuff, mucking feeding etc. but every dollar you pay out is money that isn't going in to your own pocket or back in to the barn. You have to remember that when you are hiring someone else, you are giving your paycheck to someone else.
When I had a barn liability insurance, water, power and feed are almost all of the boarding costs. B/c the actual facility was on my property my mortgage was paid for by my husbands salary, but if you're not that lucky you have to include facility use or lease costs, plus you need to factor in long term overhead for random stuff like, pasture reseeding, additional arena footing, additional turnout footing, manure removal costs, and saving for when things go wrong or saving for things to make life easier. A bare bones tractor and front loader starts around $3,000 to $5,000 and heaven forbid it breaks down. Or even worse and unfortunately far too common, a minor problem you were aware of like loose board that you were planning on fixing later in the week .. well a boarders horse OF COURSE hurts it's self on it and you are liable. You can't or don't want to file an insurance claim one something less than $1,000 b/c it will drive your deductible through the roof, so you need to cover the cost for the vet bill and all after care, and you get to care for the horse instead of eating or paying for cable or internet.
Owning and running a boarding facility is a great way to kill your love and joy for horses.