Hey everyone! Thanks for the fast replies.
Some quick deets:
We got the duck and goose together at 2 days old and raised them. Gus (the goose) imprinted on my daughter and the duck just follows the goose around.

They are about 10 months old (we got them April 23 2012)
I keep food out for them during the cold months as there isn't any verdure in their pen.
They have a kitty pool I keep fresh water in for swimming, wading, bathing.
Just to clarify, currently I am using an outside Ultrasonic Dog Bark Controller, I would never try to put the collar on my goose, either the shocking or the ultrasonic one...I don't believe in causing physical pain to any animal or human, so that's out of the question.
Also as an update, I put a new battery in the Ultrasonic device and it seems to be working better, he only screams about 5 times and then quiets down. But it's still very frequently, usually triggered by my daughter and her friends playing outside or inside (making noise), but when they are outside he just keeps going and going. I want her to be able to play outside freely without the goose annoying the neighbors etc...and if he is hearing the ultrasonic sound, which I believe he is based on his response, I don't want to cause him continual agitation either.
I really like the idea of getting him a mate,
1MrsMagoo you said I don't have to get the same breed, what is the best breed to get (that is also quiet so I don't inadvertently make the problem worse)? And do I get the mate as a gosling or an adult?
Thanks!
John