I know they need to be about 95 degrees(with cooler area if they choose away from light) and drop it 5 degrees for each week of age..I use a rubbermaid tote and right now have my week olds under a 40 watt bulb...it is plenty of extra heat as warm as it has been!
Are you using a red or white bulb? I think I need to take back the 250W- its going to be way too hot for them after a week or so.