we are parents of twin baby girls. they are 2 months old, twin 1 cries a lot and her weight is around 3 kg. twin 2 is okay but her stool colour is greyish black. the babies are on Nan Pro 1 milk.

A. Green baby poop With formula-fed infants, it's normal for baby poop to be a greenish-tan color. Sometimes the iron in baby formula can cause dark green baby poop and isn't a reason for concern. Green baby poop can also signal teething or that baby is getting over a stomach bug.