Every year, from 9 to 4 of the following year, is the peak season for brooding and rearing. Quality replacement pullets are crucial to improving farming returns. However, replacement pullets often fail to meet the target weight. What are the causes, and how can the problem be solved?
I. Possible causes of replacement pullets failing to meet the target weight
1, a high proportion of weak chicks at 1 days of age
Diseases in the breeder flock may have affected the quality of hatching eggs, or problems with incubation techniques may have led to an increase in weak chicks. Even with proper rearing and management, it can be difficult to raise a qualified flock from these chicks.
2, body weight below target before 35 days of age
Problems during this period are likely directly related to the caretaker’s management. Caretakers may not place enough importance on brooding management or understand the principle that a layer’s future is determined by 35 days of age; temperature, stocking density, humidity, ventilation, lighting, and other conditions may not meet requirements.
Failure to meet the target body weight by 35 days of age increases the number of pullets with low body weight before the onset of lay, affecting the flock’s subsequent egg production performance.
3, Feed-related factors
Although the chicks met brooding requirements and had satisfactory body weights by “35 days of age,” using excessive amounts of inexpensive alternative ingredients (e.g., cottonseed meal and rapeseed meal), together with a high proportion of these ingredients and poor-quality grower premix or concentrate, can cause prolonged nutritional deficiencies and thus affect body weight and skeletal development. If feed ingredients have excessive moisture content and are still added at the normal inclusion rate, the chickens may not receive adequate nutrients.
4, Disease issues
Failure to meet the target body weight due to disease occurring by 35 days of age (especially adenomyogastritis and enterotoxemia syndrome) can have some impact on the subsequent egg production performance of replacement layers.
5, Flock density during the brooding and growing period
Appropriate stocking density is one of the key measures for ensuring that the flock meets its target body weight.
6, Seasonal effects on body weight
The body weight within 35 days of age should not be affected by the season. Temperature management during this period can basically be controlled artificially. Even in the hot summer, the temperature at this time will not adversely affect the development of chicks (35 days of age). If body weight falls short of the target during this period due to temperature, the main cause is poor manual temperature control, resulting in a large day–night temperature difference (especially within 15 days of age), which in turn affects the development of some chicks.
7, Lighting Management
During the brooding period (within 35 days of age, especially within 7 days of age), both light intensity and lighting duration directly affect feed intake, and therefore the birds’ weight gain. During the chick stage, lighting can encourage the birds to be more active, increasing their exercise and feed intake. For chick flocks with excessive stocking density, increasing lighting at this time can address feeding difficulties caused by insufficient feeder space.
II. Solutions for Flocks of Replacement Pullets That Are Below Target Body Weight
1, Promptly Culling Weak Chicks
Promptly cull weak chicks at 1 days of age to prevent the flock’s uniformity from being affected later, which could result in replacement pullets being below target body weight.
2, Improving Feed Nutritional Levels
Depending on the specific circumstances, appropriately increase the energy and protein levels in the feed, and add multivitamins and other supplements to the feed. During brooding, use high-quality starter feed for egg-type chicks, such as Tongwei Wangchubao.
3, adjust the feed formula appropriately and in a timely manner
As chicks age, their nutritional requirements change. It is very important to adjust the feed formula appropriately and in a timely manner. Feed that is too finely ground can also lead to poorer body weight and uniformity in chickens. Chickens have specific requirements for feed particle size, and a certain amount of grit needs to be added to the feed.
4, disease prevention and control
Begin administering medication for glandular and gizzard inflammation at 3-5 days of age to help prevent the condition. At the same time, maintain normal humidity in the brooding house to prevent glandular and gizzard inflammation or necrotic enteritis syndrome from affecting flock uniformity.
5, appropriately increase lighting duration to increase feed intake
For flocks that do not meet the target at around 120 days of age, adopt the following lighting measures: 14 hours of light (flocks that meet the target may use the regular lighting program during the rearing period). If rearing takes place in summer, lights can be turned on at night from 1 to 1:30 for supplemental feeding. This helps alleviate failure to meet the target body weight caused by heat stress. After around 120 days of age, lighting for laying hens can be increased by starting in the morning (starting at 4 or 4:30; the specific timing can be adjusted flexibly according to the local sunrise time), with any remaining time added in the evening.
6, disease management for flocks that do not meet the target body weight at around 120 days of age
During this period, pay particular attention to diseases that affect flock development in flocks that do not meet the target, including coccidiosis, mycoplasmosis, intestinal parasites, and protozoal diseases. Pay special attention to stress caused to the flock by each vaccine injection and immunization, and use appropriate anti-stress medications to treat and alleviate it.