Just to clarify: Kiki is talking about the incandescent light bulbs that get hot when they are running.Also do you know that a regular old school light bulb can produce enough heat to warm a brooder in most cases?
The new, energy efficient bulbs often stay too cool for brooding chicks. If it says LED or Fluorescent, it probably will not work.
The obvious test-- turn it on for a few minutes, then sit a thermometer underneath and/or hold your hand underneath. If you can get a temperature in the right range, you know that bulb produces enough heat.