My rat Zora is 3 1/2 years old. She has an enormous growth and I think she might be in pain. I think that if I got it removed she would probably just die soon after from old age so it's not really worth it I guess. Anyway, how can I tell if she's in pain? She doesn't come to the cage door when I open it, she just goes back to sleep. She sleeps ALL the time. Her hair is thin and she is sooo slow. These are all the signs I always notice before a rat passes. But should she be put to sleep or should I let her die naturally?