I just read thro all this thread, and am sorry to hear what you've been going thro with Nanook. It really has been a roller coaster for you and the pup. I haven't noticed it in any of the other postings, but it seems this pup just can't stop ingesting stuff (sox, plastic, whatever) and that this is a lot of his problem. Wouldn't it make sense to have a muzzle on him at all times, so he can't eat anything, only take it off when he eats? You can't trust the daycare people to catch that he doesn't eat something he shouldn't. Hopefully when he's older, he'll grow out of this habit of eating stuff. My son's year old Lab ate a sock and it blocked his intestine, and it cost him $4000 (Seattle area) in surgery to remove it. So far I think you've been lucky that he hasn't developed a blockage. I dunno, if Nanook was my dog, I'd have a muzzle on him until he proved he can be trusted not to eat "junk".
"We humans are indeed fortunate if we happen to be chosen to be owned by a cat." -- Anonymous