I put my piggies out for the first time today (hadn't seen this thread!)
They didn't seem to know what to do with the grass and hid in their little house. If I put the grass in their hutch they eat it! I guess they'll figure it out, they're only little.
I've put the hutch out as well, so my sitting room isn't smelly any more, with a heater thingy under their bed. Do you think it's to cold for them to go out?