[Q-T-Pie]

It sounds like you really like your groomer so this is the approach I would take. Talk to the groomer about her assistant- let her know exactly what you saw. Maybe she doesnt know the assistant tortures the dogs in her absence. At best, your groomer will get rid of her but if she shrugs it off and keeps her there, I'd find another groomer. She might slap the cages now, but if left unchecked, those poor dogs could be next.