Because many people are raising chicks this time of the year and will use a standard brooder bulb in their setup, I think it's important to remind everyone that there is a reason you should use a $12.99 brooder lamp fixture instead of a $6.99 shop lamp fixture, or consider alternative heat sources altogether.
Shop light fixtures have a plastic ballast, which cannot withstand high heat, a lower maximum wattage capacity (lower than most brooder bulbs), and do not have a wire guard to prevent the bulb from sitting directly against the substrate should the lamp fall. They are a fire hazard, pure and simple. In fact, improper mounting of even a fixture made specifically for poultry can result in a fire; never rely on just the clamp alone to be secure enough, and take caution to keep the bulb a safe distance from the substrate and any other flammable aspects of the brooder box or coop.
Heat lamps, while low cost, really aren't the best way to keep a chick warm, however. They can throw too much heat for hatchlings, can cause burns from contact with the bulb or fixture when chicks get old enough to start attempting to roost, do not provide a normal day/night cycle, and there is even some evidence that they can damage vision. While we are sharing lamp safety in this post knowing many people will still go that route, there are numerous alternatives for providing warmth that are safer and have fewer drawbacks. Brooder heat plates, radiant heat panels, and ceramic heat emitters are all considered lower risk than high wattage lamps. For information on these alternatives and others, check out this link.
