Hen setting

Check out this thread - Ever had a winter broody? For the most part broodies can take care of the chickens themselves. You can opt to add a heat lamp on the broody to help.

 

get a lamp

 

Oklahoma chick if you weather is like mine in w Kentucky your hen may be just fine without help.I had a bantam cochin hatch a couple of easter eggers in late Nov and they are doing great and in about 2 more weeks i think they'll be taller than mom.While she was sitting the temps were dropping to about40 at nite and since they hatched we have had quite a few nites in the 20's and a couple in the teens and she did a great job of keeping them warm. The chicks are about 4 weeks old now and were outside today in the thirty's free ranging with mom and were doing fine.
I would just make sure that your girl is not sitting on too many eggs for to handle once they hatch. Maybe 3-4 max under a bantam or 5-6 under a large fowl. Remember the eggs are not a problem but you have to allow for room for her to cover growing chicks until they are fully feathered and some chickens grow very fast and are slow to feather so make allowances. while I agree that winter is not the best time to get a broody it can be done,just make sure that she has a dry draft free place to brood and raise the babies and it will be ok as long as she's a good mama.I would be ready to step in tho just in case she's not a good mom and have a brooder ready if needed
One last thought I wouldn't use a heat lamp unless I really had to.I have found that broody raised chicks seem to acclimate a lot faster than brooder raised chicks and in general seem very hardy.
If this doesn't work for you do a search on breaking broody's on this forum and try that.

 

add heat lamp or put them inside the house

 

My broodies have never had problems keeping their chicks alive in winter. I usually add a lamp though, just in case a baby gets stuck outside the nest.

 

Your hen puts out a lot of heat on her own if you do not think so let one sit on each shoulder and see how long you can take the heat

 

A friend of mine here in Virginia just had a hen hatch out 7 little babies the week before Christmas. It was cold, lows in the 20's-30's at night and she hasn't lost a single chick.

 

A hens' body temperature is about 105 degrees f. If she has a draft free coop, and the coop floor is covered with good litter (clean dry shavings or straw) to hover her brood on the chicks will be fine.