So when baby is feeding normally, diapers will show regular signs of pee and poop. But don't be shocked if the poop changes color – and develops a disturbing odor – when you begin formula ...

A study of more than 1,000 healthy babies found that almost half had green poop for at least a week sometime during their first 4 months of life, whether they were breastfed or formula fed.

If you've spotted mucus in your little one's diaper, here's what it might mean – and when to check in with a doctor.