I really like this idea, my main feeling is I wish I had more than a few second window to try to get it right. With the grass, bunnies and foxes all being a population in their own right you definitely have a challenge when it comes to the balance; I personally feel like the grass disappears too fast, but that could be a symptom of the bunnies multiplying too fast, or eating too fast. Or maybe the foxes shouldn’t multiply, and eating just extends their lifespan. Maybe the grass should respawn faster. I wish I could point you in one direction, but there’s so many ways to approach the balance and they all change the game dramatically. That’s part of why I do really like the idea. I hope you fiddle around with it some more! :3