I second everything that Maura said. A good farrier can pay their own way pretty much anywhere. My brother is a farrier and, even though he had to get a steady job due to family drama, still does it in evenings and on weekends.
Just the other day he was visiting me to trim mine and said that he made over $700 in one weekend and that was after only working for about half a day on each day.
When I was living in the city, my LT was a farrier on his days off. He said it wasn't uncommon for him to make more in 1 weekend shoeing horses than he made in a month working at the unit.
BUT, like has been said; no company insurance, no workman's comp, no sick leave or vacation time, etc. You get hurt, you're just stuck out and it is very hard on a body. It's not as hard as it used to be, since the invention of the hoof jack, but it's still not easy.
Brother complains of elbow trouble after years and years of pounding shoes into shape. Don Baskins
go-to farrier on the AQHA show circuit for decades), who is a personal friend of my family, is so stove up that he can hardly function. He's had knee and hip replacements and back surgeries galore.
Another thing that most aspiring farriers don't think about is the caliber of horse you'll be dealing with. Jason would often turn down potential clients because they expected him
to train their horses to have their feet picked up. Not all horse owners are considerate enough to have a horse that will stand nice and quiet for you to do what you need to do. If the horse does something wrong, they expect you
to deal with it, fix the behavioral problem, and still get the job done even if the horse is lunging and pulling back and pawing and kicking and biting.
Now, don't let all these negatives turn you away from it. If it's something that you enjoy, then it will be a very fulfilling and happy job. Brother would still be just shoeing horses if his wife hadn't been insistent about him getting a job with a 100% steady paycheck...even if it's not nearly as much as he was making as a farrier.