Ants are everywhere. They're the ultimate survivors. So yeah, they'd be on rooftops too. There was a food source of some sort. Maybe they were feeding off pigeon droppings, or manna from the sky......
How nice it is to find sustenance after being in a state of hunger, thirst and deprivation of the spirit. The gratitude that much stronger. The thanks that much more soul-felt.
I'm all for getting to the nitty gritty and believe in abstaining if needed rather than feel something not being authentic.
This is how I have chosen to celebrate Thanksgiving. Thanksgiving always falls on a Thursday; and I typically also get the following Friday off. From sun-up until dawn of the next day on Thanksgiving, I fast; water only. And on the night of Thanksgiving, I wander around and sleep outside, with nothing to protect me from the elements but the clothes on my back. One year I slept on the roof of a government administration building that was a couple of blocks from where I happened to be living with my grandmother at the time. The roof was covered with gravel, but I had on sufficient clothing not to be much bothered by it. It was a relatively safe place to sleep - or so I thought. I woke up int he middle of the night to find myself covered with ants!

What the hell are ants doing on the roof of a building? (This was in Florida.) That kinda sucked; but therein lies the point.
Anyway, this short and simple annual exercise really helps one appreciate both having food to eat, and warm and safe shelter. I can't tell you how good any food tastes, and how warm and soft a real bed is after doing this...
When I was younger, I'd typically be lucky to get one meal a day; usually generic macaroni and cheese. Living for quite a while like that while I was young has taught me how to ignore hunger pangs, for the most part, which is a useful skill, though can be a deficit if I get caught up in a project. The first time I ever got "busted" for shoplifting, I was trying to steal a jelly roll from Alberston’s, because I hadn't eaten in two days; they let me off with a warning; I was not such a good thief when I was very young.
And, yeah, I did the starving student thing too. It's amazing how far one can go on little more than a packet of Ramen noodles a day.
Good fortune,
- Icarus re-invents all of the holidays in their original spirits...