I just went to a local garden centre that has a 'pet corner'. Today they had put the guinea pigs and some chickens into what used to be the sheep pen and they were running around in all the space. There was a little child's summer house thing in the corner that they must live in.
I have been trying to convince DH to get some guinea pigs for a while now and I am even more determined after seeing those today.
Does anyone have a massive home-built run? If so, what is it like? Can you move it easily? Do they need to be totally enclosed to protect them? Obviously I know that I'd have to put them in at night, but I feel that foxes may get them in the day.