TechFocus_EGGS 0325 - Management Practices to Reduce Hatchi…

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Management Practices to Reduce Hatching Egg Losses By Paul Welten, Senior Regional Manager, Technical Services, Cobb Europe Profitable and efficient chicken meat production requires quality

hatching eggs. As such, management practices that impact the quality of eggs produced on the broiler breeder farm, can also have an indirect impact at the hatchery, and broiler farm.

The minimum weight for a saleable hatching egg in most markets is 50 grams. Since day-old chicks generally weigh 67 % of the egg weight, a 33.5 g chick will hatch from a 50 g egg (50 g X 0.67 = 33.5 g). However, some integrations use slightly smaller hatching eggs with a minimum of 48 grams. Smaller eggs can cause challenges such as lower hatchability and reduced chick viability, impacting broiler performance. It is recommended to weigh eggs daily. Bulk weigh at least 90 eggs immediately after the second egg collection, excluding double yolk, misshapen, very small, and cracked eggs. Plot the egg weight on a graph to monitor trends and identify potential issues that require investigation. Egg weight is often correlated with the following factors: • Body weight and sexual maturity at the onset of photo stimulation. • As hens get older they produce heavier eggs. • Poor egg production equates to higher egg weight. • Overfeeding leads to increased egg weight, while underfeeding results in lower egg weight. • Dietary energy and protein levels significantly impact egg weight. • Calcium and phosphorus are essential for the formation of eggshells and have a direct impact on egg weight. • High temperatures reduce feed intake and lead to smaller eggs. • Illnesses, parasites, or nutritional deficiencies can adversely impact egg size. • Proper water intake is essential as it is a key component of egg weight.

The condition of eggs (clean, floor, or washed) greatly affects the hatch of fertile eggs and day-old chick weight (Table 1). Table 1: The effect of egg condition on hatch of fertile and day-old chick weight

Day-old chick weight (g)

Hatch of fertile eggs (%)

90.2 78.3 81.7

41.5 40.4 40.3

Clean eggs Floor eggs

Washed eggs

(Adapted from Van den Brand et al, 2016)

Farm managers prefer that broiler breeders start laying eggs on time as a delay could reduce the total number of eggs per hen housed. Ensuring females are well-prepared during rearing is crucial for producing high-quality hatching eggs at a young age. Before photo stimulation, pullets should achieve proper frame size, body weight, and correct fleshing conformation with adequate fat reserves. Broiler breeders use a significant portion of their body reserves to lay eggs. If body reserves are insufficient, eggs will not contain adequate nutrients for the embryo and ultimately cause poor chick quality. Excessive feed restriction can result in a late onset of production, while overweight pullets face increased mortality risks from prolapse, yolk peritonitis, sudden death, and heat stress. Egg Weight Optimising egg usage begins with ensuring eggs are the correct weight and quality. Eggs that are very small or deformed are unsuitable for producing quality day-old chicks.

Nutrition Nutrition is a key factor in determining egg weight. The intake of total protein and total sulfur-containing amino acids (TSAA) significantly impacts egg weight, providing nutritionists with essential tools for its management. Research suggests that while higher egg weight may slightly increase embryonic mortality, the effect is not substantial. However, egg weight has a significant impact on fertility and hatchability (Table 2), with both metrics decreasing as egg weight increases. Table 2: Effect of egg weight on hatchability and embryonic mortality

P value

Parameter

65 to 69 g

70 to 74 g

75 to 80 g

Mid dead % Late dead %

0.0 0.73 1.63 P>0.05 2.47 5.13 6.37 P>0.05 90.7 83.38 78.7 P<0.008

Fertile %

Hatchability of fertile eggs (%) Hatchability of total eggs

95.97 93.40 88.00 P>0.05

84.67 78.67 75.33 P<0.012

Adapted from Malik et al. 2015.

• Uniformity, both in egg size and colour • Double yolks

Egg Quality Ensuring egg quality is crucial for producing high-quality chicks. Proper handling and frequent egg collection are essential, at least 4 times per day for manual nests and 2 times per day for automatic nests, to cool eggs to on-farm storage temperatures (21 °C to 25 °C). This process slows pre-incubation and embryo development while preventing physical damage from egg overcrowding in the nest or on the belt. During egg collection, the farmer must perform an initial visual inspection to ensure eggs meet hatchery standards. Key inspection criteria include: • Shell cleanliness • Upside down eggs in the tray (Table 3) • Cracks • Shell thickness

Deliver floor eggs (clean and dirty) separately from clean nest eggs to the hatchery. Floor and nest eggs should be incubated separately to reduce the risk of contamination. Factors affecting egg quality include: • Hen age - Shell colour becomes lighter and thinner increasing the risk of cracks. • Stress during the early stage of lay formation may result in more misshapen eggs. • Environment - High temperatures can cause respiratory alkalosis, leading to thinner shells. • Feed formulation - An imbalance of calcium, phosphorus and vitamin D3 levels influence shell thickness. • Feed quality - Mycotoxins in feed decreases the hatchability of fertile eggs. • Drinking water quality - Drinker water with high levels

• Deformities • Egg weight

Table 3: Influence of incubating eggs upside down on hatchability and chick quality.

Total Hatch 2nd Grade Cull Chicks Infertile

Early

Middle

Late

Large end up

89.2

1.0

0.9

2.2

2.6

0.0

5.9

Small end up

64.6

2.1

2.6

1.9

5.8

0.1

27.6

Data from a single unpublished internal trial, for reference only.

weeks. To maintain good fertility and hatchability the males should be fed according to their requirements, which will help to maintain body weight and keeps them active. Deformed and non-active males should be removed from the flock immediately. The broiler breeder farmer plays a crucial role in the poultry chain. Adhering to good husbandry practices enhances results for the farmer and positively impacts the entire poultry supply chain. References: Van den Brand, H., Sosef, M.P., Lourens, A. and Van Harn, J., 2016. Effects of floor eggs on hatchability and later life performance in broiler chickens. Poultry Science, 95(5), pp.1025-1032. Malik, H.E., Sakin, A.I., Elagib, H.A., Dousa, B.M. and Elamin, K.M., 2015. Effect of egg weight and eggshell thickness on hatchability and embryonic mortality of Cobb Broiler Breeder eggs.

of salt decreases shell weight, shell strength and could reduce hatchability . • Farm configuration - Layout and egg collection impact egg contamination and cracks. • Feed management - Rapid feed increases after photo stimulation or overweight birds, lay more eggs with double yolks. • Diseases - Infectious Bronchitis, Avian Metapeumovirus, and Newcastle Disease Virus cause a higher number of misshapen eggs. The breeder manager significantly influences fertility and hatchability. Optimal results require sexually synchronised males and females at the time of mixing to prevent stress. Over-mating, caused by a high male ratio or advanced males compared to the females, leads to stress, reduced egg production, increased mortality, and poor fertility. Conversely, flocks with under developed males compared to females have poor hatchability that persists for the life of the flock. In floor housing, the male ratio can be 1 % higher than in community housing with slats. A recommended practice is introducing 5 % of the males to the females after photo stimulation and gradually increasing the ratio to 8 % by 30

About this author Paul Welten is a breeder specialist that has been with Cobb for more than 30 years. He currently serves the EMEA region. Paul holds a bachelor’s degree in Animal Husbandry from HAS University of Applied Sciences at ‘s-Hertogenbosch.

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