Oregon, I still have mine in a brooder and DH and I have been discussing a way to get them outdoors - their pen is not quite ready for them. I was planning on moving them to their new pen this weekend, but if we cannot get that done, is a few hours per day sufficient? I work during the day, so definitely don't want them ranging when I'm not home to watch over them.
Wynette, my little guys are only outside for 15-30 minutes, depending upon the air temperature. I just put them in my fenced front yard. They eat some dandelions, swim in the dog's water dish, and toddle around.
I clean their brooder and if it is warm enough, they can stay out until they go to sleep, which doesn't take long.
Since they are just perfect snack size, I wouldn't leave them out very long without a very secure pen, and mine are supervised while they are outside. I take their brooder out with them and I clean it out there where I can watch over them.
Mine follow me, so I can make sure they get a lot of exercise just by moving from one side of the yard to the other. They will waddle after me. The swim is good, because they will flap their wings, and it is the wings that need exercise the most. The dog dish is short enough that they can get in and out by themselves and they consider it a really great toy.