When to de-worm puppies?

Question
I've been reading several informative sites but it's not quite clear when exactly a puppy should be de-wormed. My dog had a litter almost 4 weeks ago (January 7th to be exact). Also, should I have my vet do this or is it okay to purchase the OTC de-worming medication? Thank you!

Answer
Apologies for the delayed response.  The puppies are now old enough for their first deworming.  This should then be repeated one to two more applications three weeks apart.  It is possible to buy many over the counter dewormers.  If going this route I would suggest at the end of the treatments that you bring a stool sample in to your veterinarian so that they can test to make sure all parasites have been killed.

Best of luck to you and the new family additions.