be careful..I had a friend use an old waterbed heater, it shorted out and burned the entire coop down and killed the hens....!
also watch out if you use a rubber maid container, the bulb is not too close to the side, it will melt!
I would go buy a desk lamp with a bendy neck, then set it high up, use a thermometer and watch the temps...
I did the above for a couple EE babies, I actually turned the light off after 2 days, they didn't like it at all, so they went without a heat lamp from day 2, imagine that, and all the hoopla about keeping the heat at a certain temp!
**my other chicks I raised outside in the coop, and they did use a traditional brooder and heat lamp...go figure!