Delay most interaction until chicks 3 weeks post-hatch. Biggest concern coming from lots of early handling would be stressful and impose greater risk of disease, especially when birds are confined one minute and exposed to pathogens the next. Also, I would insist having so birds can perch on you / kids but actually picking up is minimized. I have small kid and he is not allowed to pick up chicks. Hens try to prevent him from causing trouble by flogging but ultimately I must tell son to leave chicks alone. Chicks are not as tough as puppies.