Susan,
It is illegal to hunt ducks with a rifle. 
It is considered by most to shoot ducks off the water as unsporting.  This is mostly by family or local tradition.  I won't do it,but won't condemn someone else if it is legal where they hunt.
Pellets in the meat is not as much of a problem as Hollywood and Ahnud & Co. would  have you  think.  Most ducks I kill have 0-1 pellets in the breast,  and  I find 99% while cleaning.  Can't remember the last pellet I bit into.  Afterall, you should be pointing for the head.  Most beginning duck hunters see this big ol bird and shoot for the body.  More cripples that way.
X-raying dead ducks?  He has too much time on his hands or doesn't hunt very much. <img src="/images/graemlins/wink.gif" alt="" />
BTW, I hunt a lot of ducks.
duckear