Good point--I might try letting them outside in the evening, as you suggested. My more skittish rabbit might be hard to catch, though, even if he is in a dog exercise pen.Red eyes shouldn't change anything much. It could just be that being outdoors isn't as comfy and they're not excited by what's there. They could be scared and don't wanna move. Rabbits are skittish - they're prey animals after all. Everything tries to eat them.
Do you think it is a problem to let them out in the same area in which the chickens go? The chickens haven't been let out lately, but I am worried that it could present a health issue for the rabbits if they eat the grass the chickens walked all over.