Can You Keep Rabbit Run And Cage On Concrete Does My Rabbit Have To Be In A Cage?

Does my rabbit have to be in a cage? - can you keep rabbit run and cage on concrete

Then I run to my room instead?
With the field pretty well.
I feel bad for him to keep me in a cage all time.its a fairly large cage, but still.i of people who build outside the case heard, but its very cold.
So, if I is a large litter box and keep it in my room like a cat?
Do you have any further advice, like keep the rabbits happy?