Even if wasting electricity is not a concern for you, there are many other reasons not to heat your coop, and very few reasons to heat your coop at those temperatures - so for your original question, yes, turn off the lamp and let them toughen up.
I was on a Canadian poultry forum the other day, and honest to God, people were talking about steps they had to take last year because their coops got too warm in the winter. I do recommend checking out Pat's ventilation page - it explains very well why this can be a problem. The lady knows what she's talking about.
If the little chickadees and sparrows do fine all winter, your chickens should be okay too.
I was on a Canadian poultry forum the other day, and honest to God, people were talking about steps they had to take last year because their coops got too warm in the winter. I do recommend checking out Pat's ventilation page - it explains very well why this can be a problem. The lady knows what she's talking about.
If the little chickadees and sparrows do fine all winter, your chickens should be okay too.
