I'm generally a paid-up member of the 'it's elf 'n safety gorn maaaaaad' crew, but in this one instance I would definitely echo suggestions to be very careful about the credentials of the place in question. Horses, as has been said, are potentially very dangerous beasts. My sister got kicked in the head by one when she was in her teens, and tho' she picked up quite a nasty gash, the doctor said she'd actually got off lightly: 'she was little more than an inch from a coma at best.'