I have no experience with heat tape, however I would be nervous that the curious chickens would eventually dig it up and bad bad things may happen.
I had a horribly cold winter, -40 during the day sometimes!!
I used a heat lamp that I attached with a pull chain, I simply pulled it on and off depending on the temp. you have to be very careful about fire!!!
also I noticed a huge problem was frostbite, I used Vaseline on their combs to help with that.
the heated whatever may be a great idea tho!!
and to those that don't heat the coop and say "they made it through the winter just fine" you try spending months outside in freezing weather with a sweater, you may survive but its torture. I prefer to prevent torture if possible lol
winter sucks im doing some more winter research aslo