Egg prices can double and then fall back within a single year, while most items in the same aisle move gently. The volatility comes from a supply chain that cannot respond quickly to anything.
A laying flock takes months to replace
Hens do not begin producing eggs until they are several months old, and that biological schedule cannot be accelerated.
When birds are lost, the replacement cycle starts with hatching and runs through months of rearing before a single additional egg reaches a shelf.
Supply is therefore effectively fixed in the short run, no matter how high prices go.
Demand hardly moves with price
Eggs are cheap relative to a household budget and are used as an ingredient with few direct substitutes in baking and cooking.
Shoppers buy roughly the same quantity whether the price has risen or fallen, which economists describe as inelastic demand.
When neither supply nor demand can adjust quickly, price is the only variable left to absorb any shock, and it moves violently.
Disease removes supply in large blocks
Commercial laying operations concentrate very large numbers of birds in single facilities, which is efficient and makes outbreaks costly.
Where highly pathogenic avian influenza is detected, established protocols require the affected flock to be culled to prevent further spread.
A small number of such events can remove a meaningful share of national laying capacity within weeks, and the replacement clock then starts from the beginning.
Feed and energy costs move the floor
Underneath the sharp spikes sits a slower trend driven by the cost of corn and soybean meal, which make up most of what a laying hen consumes.
Grain markets respond to weather, export demand and fuel costs, so a poor harvest raises the baseline cost of every egg produced.
Heating, refrigeration and transport add further exposure to energy prices at each stage.
Regulation changes housing and therefore cost
Several states have adopted requirements on how laying hens must be housed, and compliant systems hold fewer birds per building.
Producers serving those markets carry higher capital and operating costs per egg, which is why prices can differ substantially between states for an identical product.
Because supply is segmented in this way, a shortage in one regulatory market cannot always be relieved by surplus in another.
The combined picture is a product with fixed short-run supply, unresponsive demand, concentrated production and separated markets, which is close to a recipe for sharp price movement.