Hens lay more in spring-summer, less in winter. The Amish preserve eggs for half a year.
Water Glass
Sodium silicate: 1 part to 10 parts water. Fresh unwashed eggs into solution. Seals shell pores. Up to 8–12 months in a cool place.
Important
Only fresh (not older than a day). Only unwashed — washing removes the protective bloom. Store-bought won't work — they're pre-washed.
Oil Coating
Coat with mineral oil. Store pointy end down. 3–6 months. Simpler but less reliable.
Lime Water
Slaked lime — 30g per liter water. Stir, let settle. Eggs into the clear solution. 6–8 months. The oldest method — used since the 18th century.