I raise American buffs so I can't speak specifically to Sebastopol but our geese are penned at night separately from our ducks in an adjoined run/shed that is completely enclosed with welded wire. They range in the daytime with the ducks in electric netting. We determined after several fortunately not very serious incidents at night that they should not be enclosed together overnight for the ducks' safety and split their quarters. Both waterfowl tend to favor sleeping in the run at night over the shed unless it's very cold and windy. Domestic geese do not generally fly, especially Sebastopol with their quirky feathers, so they are vulnerable. My geese can clear a 4 ft fence with sufficient motivation but that's about it. Foxes, coyotes, raccoons, owls, eagles... all could be potentially problematic. In the daytime they do fine in the netting and probably do deter overhead predators from bothering the ducks as well as sounding an alert. Hope this helps! Also be aware ganders can be a handful in breeding season.