At only .55 difference per bird, I'd guess that 'pullet' means 'female sexed chick' in their language.
Timing is important here, as is atmosphere - the chicks I hatch out in February have heavy heatlamp usage. The chicks I hatch out in June are under the heatlamp the day they're born (max a week), and then they go out in a brooder in the barn with no lamp and do fine.
A lot of my chicks are fine with standard 60w incandescent bulbs. The real early ones I use 150w heat bulbs at first.
Heat lamps shouldn't cost you much though - if you're seeing huge increases in cost, something is wrong.
150w * 24hours * 30 days / 1000w = 108 kwh. Typical rates in the US are anywhere form .06/kwh to .20/kwh (.12 is average) - so anywhere from $6 to $20/month to run a 150w bulb 24 hours a day.
so anywhere from $2-6 for a 60w.
Edited by CrazyTalk - 12/11/15 at 11:46am