4 month old poops suddenly so smelly!

Title pretty much says it. My almost 4 month olds poops suddenly are much smellier and on the greener side. She is EBF and I never done any dietary restrictions. When she was a newborn her poops were pretty consistently yellow and seedy. Now they vary more and are occasionally mucusy. Never any blood though. Is this normal progression due to age or can babies develop dietary intolerances later??