Ours are pets.We got them as teens and they were very docile,still are pretty docile.Ganderz changed instantly once spring was coming upon us and it was time to figure out the new order and get mates.After this behaviour begun,the Main Gander became very protective over the cage,the nest.
Most ganders get aggressive during breeding season,but this isnt saying yours wont stay pets.Treat them like pets and see how everything goes.
Chinese have a bad rep for being aggressive. So,the bad attitude that appears during breeding season may last out of breeding season.
Lots of time ganders calm down after breeding season has had it run.