Well, it has been 12 hours and they are still at it!! I have brought them inside many times and made them rest and drink water. It seems like this is the longest they have ever stayed on a scent trail. It is all over the yard that they are sniffing. Sniffing down into the ground. We have mole crickets bad right now. I've got to get the pest control out here next week to spray the yard. Could they be going crazy over mole crickets in the yard?? It is very strange.