You have to be careful but rabbits are social animals and probably shouldn't be alone. Has Symptoms Urine Spotting. In a cage outside you're treating him like an animal and that is how he will act. They are usually silent pets with subtle body language. May be ok, depends on the cat. Grinding due to pain is often louder and more frequent than grinding due to contentment.
He could be ill.
Denver Dumb Friends League
Just like yourself, your pet rabbit may encounter some health issues along the road of life. She had scan and all clear. Rabbit can catch diseases from bird shit so make sure rabbit can't eat any by accident. Spend more time with your bunny. Communication Rabbits are often misinterpreted.