Question

Given below are two statements:
Statement (I): For laying birds, photoperiod duration should never be decreased from optimum.
Statement (II): For growing birds, photoperiod duration should never be increased from optimum.
In light of the above statements, choose the most appropriate answer from the options given below.

• A. Both Statement (I) and Statement (II) are correct.
• B. Both Statement (I) and Statement (II) are incorrect.
• C. Statement (I) is correct but Statement (II) is incorrect.
• D. Statement (I) is incorrect but Statement (II) is correct.

Hint:

Golden Rules of Poultry Lighting:
1. Never increase daylength (photoperiod) for growing pullets (prevents premature maturity).
2. Never decrease daylength (photoperiod) for laying hens (prevents drop in egg production).

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Photoperiod (daylength) is a major environmental cue that regulates the release of reproductive hormones in poultry.
Light stimulates the photoreceptors in the hypothalamus, triggering the secretion of GnRH, FSH, and LH, which govern sexual maturity and egg production.

Step 2: Detailed Explanation:
Let us analyze the lighting management principles for different stages of poultry growth:
- Statement (I): During the active laying phase, a decrease in photoperiod or light intensity simulates the onset of winter (short days).
This signals the bird's reproductive tract to regress, causing a drop in egg production and triggering a molt.
Therefore, the photoperiod duration must never be decreased for laying birds once they have started laying eggs, making Statement (I) correct.
- Statement (II): During the growing phase (pullets before the point of lay), an increase in photoperiod stimulates premature sexual maturity (precocious puberty).
This causes pullets to begin laying eggs before their bodies are fully developed, resulting in small egg size, a high incidence of prolapsed oviducts, and poor long-term egg laying persistence.
Therefore, the photoperiod duration must never be increased for growing birds, making Statement (II) correct.
Since both statements are correct, option (A) is the correct choice.

Step 3: Final Answer:
Both Statement (I) and Statement (II) are correct.