If you're unhappy, quit. Just save up a bunch of money first, and make a plan for a solid next step. But do it now and make the plan and just do the plan, don't just think about it all the time, do it.
I hemmed and hawwed about quitting my last job because my supervisors were assholes and basically swindling the public, but it was steady work and I could do whatever I wanted and I made a decent commission. So I stuck with it for 4 years, and I was so fucking depressed. I just drank all the time and was so tired, every day. then one day my hours got "suspended" (they took me down to 12 hours a week, vs. the full time I had been working for a "trial" period
) based on a bunch of made up things, and instead of just taking it, I quit. and shit was hard for a little while, but I'm glad I left and found something so much better. I don't make a ton of money, but I'm very in control of my working environment, I like my coworkers, and I'm respected by my bosses.
I gained the confidence to leave the shitty job because at one point, about a year before I quit, I took a small 1-2 day a week second job in a field I was competent in (tutoring). Participating in a different environment took me out of the routine at my shitty job. So it kinda broke the spell. And then when I quit, I just asked for as many hours as I could get at the tutoring place to keep my head above water. It ended up working out alright. I was only unemployed for about 3 weeks. Glad it happened before all this crazy mess.
I guess, in my rambling, I mean that you should take another job, or save money to go back to school. Take further training in your field. Research places that do what you do, but in a more ethical manner. Volunteer there, see about getting a permanent job there, if maybe it's a non-profit or something. I don't know. I think whatever you're doing sounds awful, I would not and could not work at a place like that in good conscience. If you love animals, you need to be an advocate for them, not a profiteer.
sorry dude, it's a sticky situation.