Deciding whether a colony needs a new queen starts on the brood frame. Beekeepers "read" the pattern of eggs, larvae and capped brood for tightness and coverage, check for scattered raised drone cappings (a sign of a failing or absent queen and possible laying workers), and note whether fresh eggs are present at all. This scene renders a brood frame whose cell contents respond live to those same signals, and computes a requeening urgency score the way an inspection checklist would.
A frame with a solid, wall-to-wall brood pattern and less than ~10% scattered gaps is the single best sign of a healthy, well-mated queen — no lab test required.
A live 3D brood-frame inspection that turns the signs beekeepers check by eye — pattern tightness, drone-layer cappings, and presence of eggs — into a computed requeening urgency score and a recommended action.
Older, failing queens produce spottier brood patterns and more scattered raised drone cappings; a queenless colony stops producing eggs and starts drawing emergency queen cells. The scene combines these into one urgency score, then models how a chosen introduction method affects the colony's acceptance of a new queen.
Drag the queen-age and drone-layer sliders to see the brood pattern degrade, tick "Queenless" to trigger emergency queen cells, then pick an introduction method and watch the worker cluster around the cage stay calm or ball up depending on how risky that method is for the situation.
Direct-releasing an unfamiliar queen into a colony that still has a viable, if failing, queen is the riskiest introduction method — workers frequently "ball" and kill her, while a slow-release candy-plug cage lets her scent spread first.