You do NOT want an uncovered light bulb! That is a real fire hazard bc EVERY form of bedding is flammable. I put a 75 watt light on a timer inside of one of those hanging electrician's work lights for my birds a few years ago, to extend their day. I wanted it for eggs, kinda like this one.
http://nationalsupplyonline.com/led-construction-work-lights.html
It produces more heat than you would think. I hope that you fixed the leak. That will cause problems down the line.
Even broodmare barns only heat to 45 degrees F bc you do not want to make the temperature too warm, else your birds won't grow the necessary feathers.
I do not heat my coop, nor do I heat my barn or blanket my horses. My 4 blankets gather dust as we speak, but they are on a shelf right above the grain in the grain room, at the ready.
Just some FYI.
I DO have an extension cord and a cover where it meets the cord for a heated dog water bowl, which keeps water even at -20. I picked up a new one recently, just in case the other one dies, so my birds always have water in the wintertime.