Getting a colony through winter

I test balance by having a script play the game on 60 different worlds for a bit over a year each and counting how many colonies are still alive. For a while they kept dying in the first winter.

Some of it was the ants not acting like it was winter. They kept burning food at the summer rate while there was nothing to forage, and the queen kept laying eggs into a colony that couldn't feed them. Now idle workers go dormant in the cold (it halves what they eat), and above 20 workers the queen only lays when there's enough stored food per worker.

Then they got through winter and starved in spring, which was a bug. If you zoned a granary a little above the floor of the chamber, the game counted the room in it wrong and read it as full, so the foragers stopped bringing seed in while the store was nearly empty.

With those fixed it's 60 of 60 alive at the end of the first winter. That's probably too safe now, I think winter should be something you can lose to if you didn't prepare, so the next round of work is making it harder again on purpose.