Hen-Day Egg Production Calculator

How it works

Hen-day % = eggs ÷ (average hens × days); hen-housed % = eggs ÷ (hens housed × days); feed/dozen = feed ÷ (eggs ÷ 12); feed cost per egg = feed × price ÷ eggs

Hen-day production is the standard yardstick for a laying flock: the eggs collected divided by the number of hen-days available, so a flock at 88% lays 88 eggs per 100 hens per day. Hen-housed production uses the number originally placed and therefore also punishes mortality, making it the better economic measure over a whole lay cycle. Commercial layers peak at 93–96% around 26–35 weeks and decline slowly to about 75–80% by 75 weeks; backyard and heritage breeds peak lower (60–80%) and drop off faster. Feed is 60–70% of the cost of an egg, so feed per dozen — typically 1.6–2.0 kg for modern hybrids, more for larger dual-purpose birds — and the feed cost per egg tell you whether the flock is still paying its way as production falls.

Worked example

1,540 eggs in a week from 250 hens (two lost): 1,743 hen-days → 88.4% hen-day, 84.6% hen-housed on 260 placed — a few points under the 94% standard at week 32. 200 kg of feed is 115 g per hen per day and 1.56 kg per dozen; at 42¢/kg the feed cost is 5.5¢ per egg.

Frequently asked questions