We have a four foot cube brooder box with chicken wire on the top and a 250 W light on top of that. Our chicks are two weeks old and maybe four or five inches tall. One of them flew so high today that it hit the chicken wire just right and knocked the light to the ground. The bulb shattered and the filaments caught on fire. Just a warning to secure the lights. No matter how small the chicks, they can fly really high. I thought we had a couple of weeks before hanging the light from the ceiling but clearly not!