If you try again IM put the chicks under her bum, don't show her the chicks at all if possible. Mums ime don't like having their chicks in front of them. I think part of this is because they know how quickly chicks chill and getting a day old chick from in front to under the bum without harming it is difficult if the hen is sitting on a bed of straw for example. I've had a few hens with chicks quite severly peck a chick that has "escaped". As soon as I tucked the chick back under the hens rear end peace was restored.