is it good to give a little bit part of an egg yellow part to a 3 months baby?

A. No please wait atleast for 5 months.The first 6 months the baby should be exclusively on breast milk feed.It takes time for their stomach to adjust so with a new born it's even more difficult.At the end of 5 months you will have to test with a bit to see it doesn't cause any reactions then you can continue but definitely not at 3 months.