Adding this here 16 years later, in case anyone else finds this thread:
My Zone 5 midwestern garden has been plagued with squash bugs for years. I do a no-till heavy mulch style garden, which allows squash bugs to easily overwinter in the mulch and explode in population the next spring.
I still grow squash, but stick to more bug-resistant varieties and do some heavy hand-picking of the bugs, with the expectation that many squash won't make it through the summer.
This past winter I fenced my ducks into the garden area every day for about 4 months (three ducks in a ~100 sq ft garden, November to March). In late March I fenced them out of the garden so they wouldn't eat my sprouts and transplants. During that time they dug their beaks through all the mulch so thoroughly that I have not found any squash bugs (or eggs) of any age in my garden at all this year, and it's now the end of June. I'm growing 6 varieties of squash, so I know it should be an enticing garden for the bugs.
I'm not sure if the ducks ate the squash bugs, since I know from summer experience that they don't like them and won't eat them. It's possible that in midwinter any bug protein seems good to them when there's no cicadas and grasshoppers nearby. They also kept digging around the mulch even in subzero temperatures (which is a normal winter here, the squash bugs didn't just go away because of a cold winter), so it's possible that the ducks just dug up the squash bugs enough that they died of the cold.