In my 8 years as a mother, currently with a 2-almost-3 month old and a 1.5 year old in diapers, I have finally figured out that there are 2 basic times a baby will poop in his diaper.
1. When their diaper is so full of pee that you’re just about to change it, but can’t get to it quite in time and so… the diaper leaks.
2. After you have just changed his diaper.
Perhaps 5-10% of in-between times.
With 7 babies in 8 years, I have never had more than 2 in diapers at a time, but I have been potty training for the past 5.5 years. Sometimes I wonder if I’ll ever be done…