My first thought: it's plastic. That could be an issue. You do not want it to melt or catch fire. Keep a close eye on it, those bulbs get super hot. And I am sure you know, if they're hot, they'll go away from the light, too cold go under it. After they are a week or two old, try a 100w if you are keeping them inside. The 250 will bankrupt you. I now have mine outside with a 100w. It gets pretty chilly at night but mine are about 5 weeks old now. I would say you could change the light in a week if they are still inside. They will let you know if they're cold.