I haven't been heating my coop (small: 4 x 4... maybe 5 feet in height). But since it's supposedly going down to 0 degrees tonight, I thought I'd put a low wattage red bulb in there. But in that color I can only find 250 watt bulbs (way too high) or 25 watt bulbs (which wouldn't add any heat really... would it?) Where can I find a 75 watt bulb? Home Depot, Walmart, and my local hardware shop don't sell them. Is there a place online someone could recommend? Thanks.