Female persistency post-peak: managing fertility and production

Causes and advice on accelerated egg production decline between 40-60 weeks in breeding stock flocks.

12 March 2025

5 minute read

By: Aviagen

Introduction

Managing breeding stock fertility and egg production is critical to achieving good breeder production and welfare. However, maintaining persistent egg output and fertility/hatchability remains challenging, especially between 40 and 60 weeks of age. This article highlights potential causes for an accelerated decline in egg production and hatchability persistency in breeding stock flocks post-peak and provides advice on addressing these challenges.

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During production, a well-performing flock has:

A predictable and uniform onset of egg production in response to light stimulation.
Pin-bone spacing of around 2–2.5 fingers (3.8–4.2 cm, 1.5–1.7 in) for more than 85–90% of the females before first light stimulation.
A steady, regular increase in daily egg production from 5% production.
A peak hen-housed egg production level of greater than 90%.
Cumulative hatchability of greater than 87% up to 64 weeks of age.
Good feather cover for age.
Positive net energy balance for males and females considering body weight and egg production level.

All traits above play critical roles in achieving hen-housed chick numbers close to the current performance objectives.

When targeted cumulative chick production is not achieved, poor egg production persistency and fertility are often the main drivers. Monitoring the following Key Management Points must be part of a daily management routine.

Rearing conditions.
Environment — temperature, lighting, and ventilation.
Sexual synchronization and mating ratio.
Body- and egg-weight control.
Production house conditions.

Rearing Conditions

The rearing period forms the foundation for the future performance of the flock. Without detailed management of all aspects of the rearing period, from brooding to mating-up, and particularly the uniformity (i.e., body weight, skeletal, and sexual) of a flock, future egg production performance can be compromised. A poorly-reared flock is less predictable, with a quicker decline in persistency post-peak and, therefore, a lower hatching egg and chick output than a well-reared flock.

Environment

Effective Temperature

The relationship between effective temperature (the temperature the bird perceives) and its effect on bird performance is often overlooked. Many managers feed the same feed amount for age throughout the year, regardless of the effective temperature that the birds are experiencing. During winter or cooler months, feed allocation may need to be increased or held at a higher, more static level as production progresses through the cooler period. During summer or warmer months, birds may reduce feed intake in response to the hot weather. Reformulate the diet to balance the feed intake so that nutrient intake fulfills the birds’ requirements.

Temperature Effect on Energy Requirements

Feed intake must be altered as the operating temperature decreases or increases from 23^oC (73.4^oF). Energy intakes should be adjusted pro rata as follows:

Increased by 6 kcal (1.2 kcal/1°C, 2.14 g/0.075 oz extra feed based on a 2,800 kcal ME/kg diet) per bird per day if temperature is decreased by 5°C (9°F) from 23–18°C (73.4–64.4°F).
Reduced by 7 kcal (1.4 kcal/1°C, 2.5 g/0.88 oz less feed based on a 2,800 kcal ME/kg diet) per bird per day if temperature is increased from 23–28°C (73.4–82.4°F).

Lighting

It is recommended that a day length of 13–14 hours of light be provided during production. Providing more than 14 hours of light during production generally leads to the flock exhibiting poorer persistency due to the advanced onset of adult photorefractoriness, and production declines more rapidly.

When open-sided production houses are used, the day length should preferably be kept to 13–14 hours, using blackout curtains at the beginning and end of each day.

Ventilation

Ventilation is a key part of the management system and should be monitored as closely as possible for the flock's life. It is essential to highlight the importance of ventilation and its link with production persistency. Ventilation must be accurately matched to bird biomass, feather cover, and external environmental conditions. Incorrect ventilation can increase floor eggs and ocular discharge and reduce egg production, daily livability, and fertility.

Sexual Synchronization and Mating Ratio

It is essential to ensure males and females are synchronized in sexual maturity before mating (Figure 1). If the facility has separate male pens and variations in sexual maturity within the male population, the more mature males should be mixed with the females first. This ensures the smaller, less sexually mature males have time to develop and mature before mating with the females. It also helps prevent less-developed males from accessing the female feeders.

In many cases where flocks exhibit lower fertility levels through peak and particularly post-peak, mating ratios are above those recommended (Table 1). It is important to check true fertility to determine the cause.

Figure 1: An example showing: (a) a mature young male with a well-developed, red comb and wattles; (b) an immature male with an underdeveloped, pale comb and wattles; (c) a young female with a well-developed, red comb and wattles; and (d) an immature female with an underdeveloped comb and wattles.

Table 1: A guide to typical mating ratios.

Body-and Egg-Weight Control

Body-weight control is critical in day-to-day management practices, but in many cases, feed allocation follows a set company profile from one flock to the next. Adjusting feed levels according to set company guidelines to stay within budgetary constraints may not allow for what a flock requires when it is over or under standard weight.

Along with body weight, monitor egg weight closely during the post-peak production period. Monitoring egg weights daily allows trends against the standard to be plotted so feed amounts can be adjusted appropriately. A deviation in the increasing egg-weight trend is often seen before a reduction in egg production and can be the first indication of a potential problem. Egg weights should be recorded daily, starting from 10% hen-day production.

Production House Conditions

Breeding flocks may be challenged to varying degrees daily. Identifying the ongoing, lesser challenges that may only be observed as a gradual change in flock persistency or reported fertility, particularly during the later stages of production, is challenging. Housing conditions should be monitored regularly, and adjustments should be made where possible.

Summary

Measuring and monitoring environmental temperature, lighting, ventilation, body condition, body- and egg-weight profiles, housing conditions, and external challenges are essential for efficiently and effectively responding to flock performance.