I wish I could comment more exactly on my two's pooping habits. I have a doggy door, and they are in and out as necessary. One of the downsides of it. Much of the time, they seem to poop when we're out jogging/walking. I suppose they're much like us, constitutionals work !
However, on the highs and lows of their appetites, that happens frequently. Both of mine seem to be somewhat coordinated on that, with them consuming a reasonable ammount for a day or so, then backing off for the same time. Their food is out 24/7 so they aren't under any "controlled" situation there either.
They are healthy and energetic, so, I just try to observant, and don't try to change their habits.