How long can 5-day old chicks be without heat?

[emorems0]

Our heat lamp died this afternoon, Dh is going to pick up a new bulb on his way home from work in an hour or two but the chicks have already been without it for a few hours. It's about 73 degrees in here (and it figures that it's only 70 outside today instead of the 85 that it has been the past two weeks). We just lost a chick... it was the smallest, but healthy otherwise and eating and drinking and pooping just fine. I think it just got too cold? Now I'm super worried about the rest of the chicks getting too cold - will a couple hours at ~70 degree temps really kill a 4-5 day old chick, or could it have been a fluke? What can I do for my other chicks in the meantime? I wasn't really that worried at first because they were just running around like normal, chirping more than typical, but not really huddled together like I would expect if they were too cold.

 

[Bethel3330]

If you think they were cold, I would utilize the oven. The stovetop on mine gets nice and toasty when the oven is on, or you could put them on a chair next to it with the door open etc. Or use a heating pad if you have one, with a towel on top...