Verdifish, you are quite right that the supplier label date of 28 days is the best thing to follow and you are not being picky in asking. There is plenty of proof regarding how different animals excrete various drugs in the science literature and of course at the detail level this is species and even individual animal specific to specific drugs but the major pathways are consistent, I had responsibility for AH drug development in 2 major pharma companies, including work on some of these wormers so my comment was based on knowledge, but I don't have papers in front of me it is not right to imply not following the suppler label except under Vets guidance. I was merely saying that poo picking in the first 48 hours is important, after that less so. Maybe worth asking your vet, although they are not necessarily knowledgeable on clearance rates.