Chickens hate change, and it can take a few weeks till they feel secure in new surroundings. They need to be kept as stress free as possible, no barking dogs, no unusual noises - like lawn mowers near them etc. No grabbing and holding on laps etc.
Once they start to settle in your granddaughter can try just sitting near them - reading or maybe listening to soft music, so they see she is not a predator. She can bring them treats now and then to earn their trust.
Is you GD raising them in similar situation like you do with yours?