Yep, sounds almost exactly like my experience at Petsmart.

When I was hired, the manager was cool and seemed to care. A week later, she was transferred away and they brought in the manager from Heck. She was also a recent graduate and thought she knew everything...about managing. She knew SQUAT about animals!
The scheduling thing - same here. I signed up for Part Time, saying that I couldn't work more than 30 hours a week with no back-to-back long shifts. This was stated in a Doctors note...twice! The result: she scheduled me regularly for 38-39 a week, with two 10hr shifts back to back! She also expected me to 'work as fast as she did' and always told me I was 'too slow'. Ok, one: I couldn't move very fast, as per the doctors notes. Two: you do NOT move fast when working with skittish, cramped animals! I stayed and put up with all that crud for 9 months...but could finally take it no longer.

To make a long story short, I did similar to what you did by turning in the keys and such... but I included a long letter to the general manager of the area which outlined her treatment of me, the animals, and my co-workers. I found out she was fired a week later.

Good for you for leaving such a horrid situation!