My parents have asked us to look after their Lab / Pitbull mix for 1 week while they are on vacation. We are having a blast with him, he is such a good dog. (We are hoping he will rub off on Daisy & Duke!)[

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We have had him for 48 hours and he hasn't pooped yet! He is used to having free roam of my parents 50 acre farm and with us (because he is an escape artist), he has to be inside. And because he has free roam, they don't know his bathroom patterns. We have taken him on TONS of walks in fields, trails, and forests. But no Poop! We take him out almost every hour as we have a 12 week puppy that neeeds to be taken out. But he won't go. He pees lots and has been eating his meals.
I have never owned a "big" dog before, only my wee little ones. For them not to go poop in 48 hours would be a big problem.
For you guys with Big dogs, is this normal or should I be worried????