Broiler Breeders - Lecture Notes Review (copy)

Broiler Breeder Industry Overview

• Broiler: Chickens raised primarily for meat production.

• Broiler Breeder: The parent chickens of broilers that lay hatching eggs.
    - Parent chicks sold by primary breeder companies.

• Primary Breeder Companies: Entities that own grandparent, great-grandparent, and pedigree lines, selected over years for marketable traits.

Genetic Pipelines and Stock

• Genetic Hierarchy:
    - Integrator
    - Primary Breeder
    - Pedigree Elite Stock
    - Great Grand Parent Stock
    - Grand Parent Stock
    - Parent Stocks
    - Broilers

• Growth and Production Figures:
    - Year 0: 400,000 birds.
    - Year 1: 500,000 birds (cumulative total).
    - Year 2: 12,000,000 birds.
    - Year 3: 300,000,000 birds.
    - Year 4: 400,000,000,000 birds.

Genetic Lines of Major Breeder Companies

Aviagen/Ross:

• Female Lines:
    - Ross 708
    - Ross 308
    - Ross 308AP

• Male Lines:
    - Yield Plus (YP)
    - Efficiency Plus (EP)

Cobb-Vantress:

• Female Lines:
    - Cobb 500
    - Cobb 800 (2026)

• Male Lines:
    - MX (discontinued)
    - MV (discontinued)

Examples of Crosses:

• Ross YP x 708: Results in large birds suitable for deboning.

• Cobb MX x 500: Historically noted for superior feed efficiency.

Selection Criteria for Breeder Lines

Male Lines:

• Selected for:
    - Rapid growth
    - Meat characteristics (breast width, carcass yield)
    - Livability
    - Feed conversion ratio
    - Fertility

Female Lines:

• Selected for:
    - Outstanding growth rate
    - Meat yield
    - Feed conversion ratio
    - High hatchability
    - Good production of eggs with desirable size and texture.

Broiler Chicks and Hybrid Vigor

• Broiler Chicks:
    - Result from a four-way cross of genetic lines, where a combination of male and female strains produce hybrid vigor (heterosis).
    - Hybrid vigor refers to the offspring exhibiting superior traits compared to the average traits of the parents.

• Terminology:
    - Referred to as a ‘terminal strain cross’.

Broiler Breeder Management

Terminology:

• Pullet: Immature female chicken.

• Cockerel: Immature male chicken.

• Hen: Mature female hen that has laid eggs previously or is actively laying.

• Rooster/Cock: Mature male that has produced or is producing semen.

• Replacement Flock: New flock of pullets set to replace older hens on a breeder farm.

• Placement: Introduction of new breeder chicks into the pullet house for rearing.

• Breeder House: Housing for pullets and cockerels with a stimulated increase in daylength.

U.S. Breeder and Hatching Egg Production Statistics

• Annual Production:
    - Approximately 120 billion hatching eggs produced yearly in the U.S.
    - Approx. 150 chicks per hen translates to 80 million breeder hens and 8 million roosters.

• Alabama Statistics:
    - 1.2 billion hatching eggs produced per year.
    - Contains 8 million hens and 0.8 million roosters.

Goals for Rearing Broilers

1. Ensure health and low mortality rates.

2. Achieve high production of fertile eggs and quality chicks.

3. Maintain economical and low feed consumption levels.

Broiler Breeder Paradox

• Efficiency: Broilers optimized for rapid growth due to virtually unlimited voluntary feed intake.

• Challenges: Balancing acceptable reproduction and health against hunger stress and compromised welfare during growth and reproduction phases.

Feeding Programs and Management

Feed Restriction Programs:

• Goals Include:
    - Maximizing egg and chick production.
    - Reducing metabolic disorders and mortality in broiler breeders.

• Key Aspects:
    - Control body weight
    - Ensure flock uniformity
    - Provide adequate nutrition for weight maintenance and egg production.

Critical Factors Influencing Breeder Goals:

• Environment

• Lighting

• Nutrition and Feeding

• Health

• Behavior

• Genetics

Phases of Broiler Breeder Management

1. Brooding Phase: Days 1 to 7 in the rearing house.

2. Rearing Phase: Weeks 1 to 20 in the rearing house.

3. Laying Phase: Begins at 21 weeks in the layer house.

Brooding Phase Details

Preparation for Arrival:

• Barn conditions need to be optimal, similar to broiler houses:
    - Maintain critical temperature, adequate ventilation, fresh litter, and CO2 levels less than 3000 ppm.

• Two Brooding Types:
    - Spot Brooding
    - Whole House Brooding

Temperature Guidelines:

Spot Brooding Considerations

• Temperature Effects:
    - Too High: Chicks become quiet, pant, droop wings, and move away from the heat source.
    - Correct Temperature: Chicks are evenly spread and noisy, indicating contentment.
    - Too Low: Chicks huddle and exhibit distress calls.

Whole Barn Brooding Considerations

• Temperature Effects:
    - Too High: Chicks actively move away from heat sources.
    - Correct Temperature: Evenly spread chicks.
    - Too Low: Chicks huddle together for warmth.

Pullet Rearing Phase

• Structure:
    - Rearing houses must be sex-segregated to allow distinct feeding and selection for males and females.
    - Acknowledges that mixed-sex rearing can lead to uniformity issues.
    - Males tend to dominate feeding, negatively affecting female reproduction.

• Duration: Pullets remain in rearing houses until approximately 20-22 weeks.

Stages of Pullet Rearing:

• First Stage (0-6 weeks): Focus on developing frame size and uniformity.

• Second Stage (6-16 weeks): Controlled feeding to manage body weight.

• Third Stage (16-24 weeks): Promoting growth rate for sexual maturation.

Feeding Practices for Broiler Breeders

• Feeding Strategy:
    - Broiler breeders primarily undergo feed restriction throughout their lives.
    - Initially, chicks are fully fed for the first 3 weeks.
    - Broiler breeders at 24 weeks should weigh 5 lb under feed restriction; non-restricted would weigh 9.5 lb.

Feed Restriction Trends

• Increasing restrictions have become critical over the years:
    - Trends monitored (1957, 1978, 1995, 2015) show consistent levels of restriction despite increasing growth potential.

Implications of Feed Restriction

• Feed restriction aims to prevent reproductive issues while enhancing production metrics:
    - Delays in egg production initiation due to excess weight.
    - Reduction in double yolkers and improved production rates.
    - Enhanced fertility and increased hatching eggs.
    - Lower mortality rates in laying houses, especially sudden death syndrome.
    - Produces smaller hens with reduced maintenance requirements.
    - Adheres to defined body weight standards while addressing welfare concerns.

Weight Management Techniques

• Weekly weight monitoring should involve 50 birds, or 2% of the flock:
    - Aim for flock uniformity within ±10% of average target weight.

• Flock Grading: Separate birds not meeting target weights to manage their growth effectively.
    - Considerations for grading vs. no grading practices.

Feeding Protocols Overview

• At least three feeding phases identified:
    1. Pullet Starter: Day 1 to 4 weeks.
    2. Pullet Grower/Developer Diet: 4 to 18-23 weeks.
    3. Breeder Diets: After 24 weeks to 45 weeks or beyond.

Lighting Management in Rearing

• Daylength is strictly managed across rearing phases to control sexual maturation and overall bird performance:
    - Must adhere to the following rules:
      1. Daylength must never increase for growing pullets.
      2. Daylength must never decrease for hens.

Photostimulation in Reproductive Activation

• Photostimulation: Application of extended daylengths to activate reproductive behaviors.

• Chickens are natural seasonal breeders; longer day lengths (>12 hours) stimulate reproductive activity through the hypothalamic-pituitary-gonadal (HPG) axis, prompting:
    - Ovary development.
    - Oviduct development.
    - Yolk production.

Importance of Lighting Prior to Photostimulation:

• Photoperiod for pullets should be less than 12 hours for continued growth.

• Extended photoperiod negatively affects pullet sensitivity at maturity and egg production onset.
    - Leads to reduced peak productivity and cumulative egg output, thus lowering hatch rates.

Lighting Program Parameters

Sexual Maturation Overview

Males and Females

• Maturation indicators based on age and body condition.

Laying Phase

• Transition of broiler breeders to layer houses occurs at 18-21 weeks:
    - Key features include providing designated water lines, feeders, sex-separate feeding, littered mating areas, slatted floors, nesting areas (both conventional and mechanical), and perches.

Nesting Requirements

• Types of nests provided:
    - Conventional nests
    - Mechanical nests

• Nesting is essential for hens for a sense of security:
    - Preference for enclosed, concaved surfaces with loose nesting material.
    - Reducing competing nesting sites to lower egg damage or contamination.

Broiler Breeder Housing Considerations

• Includes adequate bedding, nest boxes, feed, and water availability.

Practices for Effective Feed Distribution

• Key Management Practices to ensure uniform productivity:
    - Address distribution of females and males around feeding stations to maximize access and minimize competition.

Lighting Protocol in Laying Stage

• Maintaining a lighting regimen between 11L:13D and 14L:10D is crucial, avoiding extremes that lead to male photo-refractoriness.

Age Related Lighting Adjustments:

Mating Practices in Breeders

• Natural Insemination: Occurs during a mating dance performed by males, with responses from females indicating receptiveness.
    - Highest activity occurs in the afternoon/evening.
    - Males' sperm can stay viable in the female's oviduct for 2-3 weeks.

Influencing Factors for Mating Behavior:

• Age

• Body Weight

• Size

• Population Dynamics (male:female ratio)

• Physical Condition

• Pecking Order

Artificial Insemination Usage

• Primarily used in pure lines, especially within the turkey farming industry.

• Advantages include:
    - Improved fertility rates.
    - Reduced damage risk to females.
    - Ability to manage smaller volumes of semen effectively.

• Drawbacks: More expensive and labor-intensive.

Performance Metrics and Targets

• Primary performance goals include:
    - Fertility rate: 92%
    - Hatchability rate: 85%

Mortality Rates Throughout Breeder Production:

• Rearing: 4-5%

• Laying: 8%

Monitoring Practices for Breeder Management

Body Weight Tracking

• Weight management strategies involve using electronic scales for chick weights during early rearing stages and total bird weights later.
    - Sampling points established during the laying period to ensure consistent monitoring.

Monitoring Feather Condition

• Female feather loss may indicate increased mating activity or imbalances in feed management and nutrition.

Assessing Male Condition

• Evaluation involves palpation of keel bone prominence and assessment of breast shape and condition as indicators of overall health and condition.

Male Fleshing Score System:

• Monitoring shows physical signs of activity (feather wear) or inactivity.