Access outdoors for indoor rabbits?

Hi

Does a rabbit that lives indoors require access to grass outside or is this not necessary provided it is getting the right diet and plenty of exercise indoors?

If it should be getting outside daily, how much time out each day is best?

Thanks

I have two house rabbits and Wesley enjoys going outside, Honey is not so keen. I feel it gives them a different routine. They only go out when it is nice and not wet as they are not used to the cold. I don't think they have to go out but I feel it is nice to have a different routine.

Thanks, do you have a hutch and run outside for them? Or just a run?

I have runs with little plastic igloos inside for shelter and tunnels. I only have a playpen at the moment for Wesley which is collaspable so they are not left out unsupervised because of neighbours cats.