Asterion and the animals rights

I don't consider myself an animal lover but that doesn't mean that I dislike. In fact, there are some animals that I like, for example, I like dogs, horses, monkeys and crocodiles. My first pet was called Asterion, and was a hamster, I really loved, he used to live freely throughout the house, I find it very right because this attitude respect animal rights, i think everyone with a pet should let them live free, not mistreat them, give them love and of course, a lot of food. the destiny of my pet is very rare ...... One day,  when night had fallen, Asterion had not returned as usual. we started to look and found dying behind the washing machine. we took him to the vet and the vet told us two things:

1) Asterion is not a man is a woman
2) His death was caused because a big mouse raped
All this leads me to ask me a question open to the public
if we give way too free an animal, this freedom would not be dangerous for the animal?