Should I bring in caterpillars to save them from cold weather outside?

Sometimes it's just best to let nature take its course. We could raise thousands every year, and I only bring in about 100 over the course of the season. If you're planning to raise them, that's great, but...

Trying to raise them all (especially in continuous growing regions) can create milkweed shortages, disease issues from overcrowding, and place too much stress on you. Monarchs that don't survive outside will serve the ecosystem in other ways.