Ahh, the problem with conversing online, where we can't see each other's faces! I've read enough of @aart 's posts to know he's a jovial guy and meant his post in jest. But it can be hard to read that without knowing someone...I can see how you easily could have perceived it as "attitude". You know, one person's joke is another's insult.
Do you know the wattage of your heating mat? That sounds very good at -18F! Also, have you noticed a difference in your electric bill using the seedling mat versus the stock tank heater?
Also, allaboutchickens.com does not seem to exist anymore. That link send you to a generic ad-based website. I recall visiting her site in the past and it wasn't what is showing up now.