Sorry Tom, I know how you feel, but it's a case of "Love my dog, love my dog's crap!" It's a package deal here, dude.
And seein' as how the little "gifts" your dogs leave in your back yard is a natural phenomenon, why would you take it out on them and threaten to send them away if it's the "other family members" who aren't pullin' their weight in this regard.
MY suggestion...tell those "other family members" that IF they DON'T start helpin' out their dad, AND those two other four-legged "family members", THEN they're NOT going to do a D*MN THING ELSE, such as video games, goin' to Chuckie Cheese, oh, I don't know, maybe even leaving the house to go to little Mikey's down the street, UNTIL they DO do the doo-doo boogie!!!
AND...you HAVE to MEAN IT!!!
(and DANG IT!!! If only I were fat, bald, spoke with a folksy Texan accent and knew Oprah, I could be rich beyond belief by dispensing these common sense solutions to these everyday problems TOO!!!)
