Peak HDP (daily)
93.4%
Closed 96.6% vs Open 90.1%. Brown-class breed guide: 93–96% at 26–32 weeks.
HDP >90% Persistency
15.1 Wks
Closed 30.2 weeks, Open 0 weeks. Open's weekly average never reached 90%.
Cycle Egg FCR
2.258
Closed 2.096 vs Open 2.420 kg feed per kg egg mass. Healthy range 2.00–2.15.
Egg Reject Rate
3.98%
Closed 1.35% vs Open 6.61% (cracked, thin-shelled, abnormal). Control limit < 2%.
Finding 1 · Persistency & output per bird
Closed houses held HDP above 90% for 30 weeks. Open houses never got there.
Closed flocks averaged a 96.6% peak HDP and stayed above 90% for 30.2 weeks. Open flocks topped out at 90.1% on a single peak day, then hovered at 82–84% under 31°C ambient temperatures and 83–85 THI. The bottom line: 351.5 eggs per hen housed in Closed vs 255.3 in Open (−96 eggs, −27%), with Open mortality at 26.6% vs 5.9%.
Finding 2 · Feed efficiency
A 0.324 FCR gap saves IDR 2,550 per kg of eggs (±IDR 1.7 billion per 30k-bird cycle).
Cumulative FCR ran at 2.096 in Closed vs 2.420 in Open (a 0.324 kg feed per kg egg mass gap). At an average feed cost of IDR 7,890/kg, Closed houses saved IDR 2,556 per kg of eggs produced. For a 30,000-bird flock yielding ~675 tons of eggs per cycle, that efficiency preserves IDR 1.72 billion in cash.
Finding 3 · Shell quality
Reject rate dropped nearly 80% (1.35% vs 6.61%) with temperature control and mechanical handling.
In Open houses, daily THI of 82–86 triggered chronic panting that depleted blood bicarbonate ions, causing thin, brittle shells. Combined with manual collection, Open rejects reached 6.61% (1.23 million eggs). Closed cut this to 1.35% through evaporative pad cooling and cushioned egg conveyors.
Closed vs Open House: 7 metrics over 60 weeks
Weighted averages per house type, reflecting active filters.
| Evaluation Metric | Filtered Closed House | Filtered Open House | Relative Delta | Operational Impact |
|---|
Hen-Day Production (%) Trajectory (Weeks 18–77)
Production dynamics benchmarked against Brown-class breed guide
Filtered Closed House
Filtered Open House
Brown-class Breed Guide
Egg Weight Maturation Trajectory (Grams per Egg)
Egg size progression with flock age (57.4g → 66.3g)
Weekly Feed Conversion Ratio (kg Feed / kg Egg)
Feed efficiency from lay ramp-up (W22) to cycle end (W77)
Physiological Analysis of Laying Persistence:
Both housing systems ramp up production toward W24–W25. Beyond W38, heat stress in Open House accelerates post-peak lay drop to 0.53% weekly (Closed held at 0.38% weekly). Closed House automated 16-hour photoperiod preserves consistent LH and FSH release regardless of cloud cover.
Both housing systems ramp up production toward W24–W25. Beyond W38, heat stress in Open House accelerates post-peak lay drop to 0.53% weekly (Closed held at 0.38% weekly). Closed House automated 16-hour photoperiod preserves consistent LH and FSH release regardless of cloud cover.
Temperature-Humidity Index (THI) vs Egg Reject Rate
Correlation between ambient heat stress and eggshell integrity
Reject Rate (%)
THI Index
Biological Mechanism
Respiratory Alkalosis & Calcification Failure
When THI exceeds 78.0, hens pant rapidly to shed metabolic heat. Excessive blood CO₂ exhalation raises blood pH into alkalosis, depleting bicarbonate ions (HCO₃⁻). The uterine shell gland cannot bind calcium to precipitate calcium carbonate (CaCO₃) crystals, causing thin and cracked shells.
Litter Management
Manure Belt Dryers vs Ammonia Gas Buildup
Closed House units run polypropylene manure belts with active air drying, keeping ammonia at 5.5–9.2 ppm. In Open House sheds with open droppings pits, wet manure produces up to 29.5 ppm ammonia, damaging respiratory cilia and elevating flock vulnerability to respiratory infections.
Hydration Balance
Water-to-Feed Ratio Under Tropical Heat Stress
In climate-controlled Closed houses, water-to-feed intake stays balanced at ~1.85 ml per gram of feed. In Open houses where midday temperatures exceed 32°C, water intake spikes to 3.2 ml/gram as evaporative cooling compensation, producing watery droppings that soil eggshells.
Gross Margin Sensitivity to Egg Price Fluctuations
Egg operational break-even (BEP): Closed IDR 22,550/kg vs Open IDR 25,470/kg
Financial & Production Matrix: Filtered Flocks
Detailed breakdown of egg revenues, feed expenditures, spent hen salvage, and net margins
| Flock ID | House Facility | Type | Strain | Housed Pullets | Mortality | HHP (Eggs) | Peak HDP | Egg FCR | Reject Rate | Net Profit | Margin/kg |
|---|