The birds like millet and they can eat that at a day old you should try some. Just put some on your hand and stick it in if one of them starts to like it they all will like it. I give it to them before bed so if it expand in their stomach (because it is used as a cereal) they won't wake up as...
I am so sorry for your loss I lost all my chickens last year and I am only a teenager so it was very tragic. I have heard that if you spray the new chick and the others with the same perfume and equally pet them they should get along fine:)