Stool Sample

Question
I am taking my dog to vet for a regular examination and other shots he needs. I was asked to bring in a stool sample. Well, I have two dogs which are both outdoor full time. I don't feed them "breakfast, lunch and dinner." I just leave food in their bowls, and they eat whenever they want to. I cant just look through the yard to find it because I have two dogs and I don't know whose is whose. If I do see him poop, I don't want to collect it to early. So, I would like to know what I could do and within about how many hours should it be collected and taken in to the vet so it is still "fresh."

Answer
I would just collect whatever stools you find and have the composite examined. If one dog has parasites, the other will most likely have them, too.

It really isn't a good idea to leave food out for them to munch on at will. One may eat more than his share and put on too much weight, which isn't healthy for any of us, and a dog should never think that food just "grows" there, as he needs to know that WE control its resources. In addition to that, food left out will draw in various vermin like rats, raccoons, etc. Feeding once a day is sufficient for most dogs, although some people do prefer to feed twice.