Your secondary may have kicked in, too, if your primary allowed the temp to reach the secondary's minimum. Glad you got it back working.
Two nights ago, a big storm took out our power for nearly 4 hours. I was awake when the power went out, so we immediately jumped up, closed the vents, and covered the 416 with blankets. Three hours later ( at 2 in the morning), temp in the gator had dropped to 90 and the lightening slacked enough for me to feel safe in cranking up my motorhome's generator to power up the Leahy. Just as temps reached 95, the power came back on, and just as I got the genny shut down and the cords put away and the leahy back on city power, the power went out again. This time, thinking that the outagel would be short-lived since it had just been on, I didn't go back out and crank the genny. Another hour passed until it finally came back on. Temps never dropped below 90, and the hatch that was due today is happening on schedule. I am very impressed and pleased with this machine! Had it not been so well built, temps would have dropped like a rock and our hatc would have been even more threatened.
We had chicks in the brooder, too. To keep them warm while the power was out, I opened up some of my Hot Hands leftover from deer season. You know, the cheap little iron oxide packets that get warm when exposed to air. I set them under a paper towel, and the chicks snuggled up and went to sleep on them. Worked like a charm.
Another Leahy tip: The fellow we purchased ours from, a hobbyist restorer of these machines, replaces original fans only if necessary. To get one working again, he first blows it out with compressed air, then oils it. He says that, 9 times out of 10, this works. Leahy says to use a penetrating oil on the bearings if fans seems sluggish. If necessary, though, this restorer uses ventilating fans from oven/range vents. He says they are a bolt-on replacement, built to last, quiet, and available cheap either used or new.