Barn work is hard physical work for minimum wage, and it is often split shift work (mornings and evenings) and often not full time. In general unskilled barn work means mucking stalls, feeding horses, and taking horse for turnout. It does not involve training or riding horses, and it does not lead to that either.
You will not have time or energy to ride, and you will risk being injured either repetitive stress injury, or a bale of hay falling on you, or by a horse. Even the nicest barn is not particularly friendly, at least to the chores person. You will be at the bottom of the hierarchy, you will be keeping your head down to get everyone fed and cleaned, and the full board clientele (some of whom will no doubt be engineers) will swan in three or four days a week to take lessons on their expensive horses. I say this because only in relatively expensive barns can you expect to be paid for the work. In more marginal barns, a lot of the work is done by teens working off board and lessons in barter.
There will be no career advancement and you will not advance to being a trainer or a coach. You will just be the cleaning lady forever.
Indeed, I think being a cleaning lady is probably less work and better pay than working in a barn (judging from what the independent cleaning ladies I’ve hired get paid).
Living on minimum wage is just about impossible, and there will be no benefits or pension.
If you have an independent income such that you don’t need to work, then just don’t work. If you need an income, cleaning barns is unlikely to keep you going.
I would suggest that if you are unhappy with the jobs in your field that you have, that you try to find a subspecialty that interests you even if it means taking a pay cut. Would you feel better about a job in environmental engineering? Working for an NGO building infrastructure in a developing country? Working for a nonprofit building affordable housing? What is it about your job that you feel “you don’t fit in?” What would it take to find people that you could be more comfortable with?
If you do want a full time job mucking and grooming, one place to go is the local racetrack. They are always looking for people and they tend to pay better than riding barns, though not that great. I don’t know if they are friendly places or not, much will depend on the individual trainer. The horses are hot and can be a handful, and you will learn alot about legs and wrapping and coldhosing and hotwalking, but might see some practices that you don’t feel entirely comfortable with, from a horse welfare perspective. But that is almost a guarantee when you go into the pro side of any horse business.
Typically people start work at 6:30 am and end around 3:30 pm at the track, but the day will be longer if you are required to stay around for afternoon or evening races.