Effect of O₂ Drop on Hatchability

Correct Answer: 5%

For every 1% fall in O₂ level below the optimum of 21% in the incubator, hatchability drops by 5%. Similarly, every 1% rise in O₂ above 21% raises hatchability by 5%.

Incubator Gas Requirements

• Optimum O₂ level: 21%
• Optimum CO₂ level: 0.5%

CO₂ Rules

• Every 1% rise in CO₂ above 0.5% → increases embryonic mortality.
• If CO₂ rises above 5% for a prolonged period → all embryos die, hatchability = 0%.

Temperature is Most Critical

Among all incubation factors, temperature is the most critical factor. The optimum temperature during days 1–18 is 37.5°C (99.5°F), and 37.2°C during the last 3 days (hatcher). Even 1–2°C deviation can cause embryonic death or malformations.