They really all seem to vary for me and it seems like the smaller ones poo more often. Gracie (9 lbs.) Goes once in the morning and once at night. Sugar (3lbs.) goes twice in the morning and once at night. Then we have my daughter's dog, Spike(4 lbs). Twice in the morning, once during the day, once at night and he wakes up in the middle of the night and poops in her room.
Major poop machine! He also pees way more than the other two. I also fee 1/4c food (Merrick dry) twice a day.
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"If you have men who will exclude any of God’s creatures from the shelter of compassion and pity, you will have men who will deal likewise with their fellow men." — St. Francis of Assisi, 1181-1226