Wow 9 yrs old! Congrats on such long living ducks.. Duck dementia? I didn't know they could get dementia. I have 2 Males and 1 Female. I'm desperately looking for a female but it seems most people I get in contact with either don't have a clue what their geese are or will only sell a pair. And I don't need an extra gander. I'd hate to buy a pair just for the female and rehome the gander because that's just too much on them I'd think. So for now I'm just looking and looking and will hopefully find the perfect match for my geese.
I call it duck dementia not sure what it is actually, sometimes she will act confused and start running around. When I see her do this I pick her up and put her in her bedroom till she calms down. I have added extra vitamins to her water for a while and she has been doing better, Her and her sister are inseparable so I can't put one up without the other.
I hope you can find a goose for your gander, they get so attached to each other I can understand your reluctance in separating a pair so your gander to have a mate, It took me along time to find a goose for my gander. They are such a sweet pair. Since Cheese is a Pekin maybe she would make a good mate for your spare gander. Just a thought, my gander had a Muscovy for his mate for 6yrs till I got Missy my goose.