I would strongly recommend getting two females. My Buff girls are practically inseparable; they call to each other if one gets out of the other's sight. They sleep together, eat together, walk around together.
Maybe because there's no gander, they also fiercely defend each other's nests and...
@nuthatched has suggested some great links!
In my experience, geese and chickens probably shouldn't be housed together. I let my geese, runner ducks and chickens mingle freely during the day, but everyone has separate sleeping quarters. The size difference, coupled with the tendency of my geese...