It sounds like googling may not be your strong point
"California Overtime Veterinary" and BOOM! first hit
Are you asking out of curiosity, or are you feeling slighted at your workplace (or as you say, feeling slighted for your co-workers) for one reason or another due to the work hours? It kinda sounds like the latter. If you have a problem with certain things, why don't you just go to the practice manager or the owner and have a civil discussion about it? But only do so if it's something that actually really bothers you and inconveniences you.
Especially in small businesses, there are very few places that follow the minutia of every labor law (or OSHA, or whatever) to a T. Just nitpicking anything and everything that a practice could be doing
wrong would be just plain annoying. Of course there are things that just cannot be ignored (e.g. not getting a paycheck when you're supposed to, not getting overtime when you're supposed to, etc...), and that kind of thing needs to be dealt with promptly.