Chicken is a viral infection and usually subsides within 7-10 days. It spreads by droplets after sneezing or coughing. Once all fluid filled lesions are subsided forming a dark coloured xruat, a person having chickenpox does not transfer it to others. Till that time, close contacts who never had chickenpox should stay away from the person. Ask her to take enough rest, eat balanced diet and drink lot of water. Visit a dermatologist for treatment for faster recovery.