Get a thermometer to put in your brooder to monitor the temperature. They will move away from the heat if they get too warm, and huddle together in the heat if they get too cold...so you can watch that, too. But if the heat is such that they can't get far enough away from it, it will stress them out. You can get stick-on thermometers from pet shops that are used for reptile keeping. They're pretty cheap.
Check out the Chicken Chick's website for lots of tips on pest control and all stuff chicken. Also, My Pet Chicken is a good website. They sell chicks mail order, but have a pretty good reference section. I also bought their paperback chicken book; didn't know it was theirs until I got it, but I think it's the best book of the half dozen or so chicken references I purchased! It's called (not surprisingly) the "My Pet Chicken Handbook". Got it off Amazon. Good resources to check into!
Make sure the heat lamp is SECURE at all times; if that thing falls over and touches something flammable, it's a fire hazard. Those 250 watt red bulbs are HOT! So keep your little ones away from it, too, and make sure it's well attached. And enjoy your little balls of feathers!