How much do you make from being a horse breeder?

I am going to be a horse breeder. I just moved and got myself a nice house with 15 acres and a barn with 10 stalls. I didn't get this house for the barn. The house is really nice. My friend said now that i have a nice country house i should breed horses. It sounds like a good idea to me. I would make a little extra money, plus i have always liked horses and it would be cool to see the babies grow up. About how much money do you make being a horse breeder? What types of horses should i breed? I want to breed something really big. Should i turn back on the eletric fencing? And i was going to keep the male with the mares in the pasture all the time besides when they are having the colt. I am going to put the male in a stall when the girls are foaling, is there any toys i can get him to keep him entertained while he is in his stall?