my baby is 6 months 20 days old. For 3 months since birth he was on top feed as well as breastfeeding. then stopped formula milk and he was exclusive on breastfeeding. and now he is on semi solids as well. after stopping the formula milk since that time his stool colour is green. till 6 months stool was of flowing consistency but after introducing solids stool is of normal consistency. but unable to understand why for 4 months approx the colour is such