Nate's right about that, but generally healthy snake poop looks like poop. You shouldn't really notice a lot of hair in it unless it thoroughly dries and breaks up. And...there ain't no way that your snake completely digested and defecated that mouse in only 3 to 4 days. Defecation could have been from a previous meal, but should have looked like ordinary every day poop. If it looks like a partially digested mouse, it probably was a regurge. Can you get a little more specific about what you saw????

Steve