FERTILITY DISORDERS IN COMMERCIAL  POULTRY (LAYERS & BROILERS ) BREEDERS/ PARENT STOCK 

FERTILITY DISORDERS IN COMMERCIAL  POULTRY (LAYERS & BROILERS ) BREEDERS/ PARENT STOCK 

Compiled & Edited by-DR. RAJESH KUMAR SINGH, (LIVESTOCK & POULTRY CONSULTANT), JAMSHEDPUR, JHARKHAND,INDIA
9431309542, rajeshsinghvet@gmail.com

 

Fertility Disorders In Breeders

Infertility caused by male management problems is common. Problems may be caused by an inadequate number of healthy males or because males have reduced sperm production resulting from chronic disease, inadequate feed intake, or starvation (harsh feed restriction). However, obese females may be less efficient in transporting sperm to the infundibulum, resulting in reduced fertilization of the ovum as it is released from the ovary. The male must be dominant to the females, or mating will not occur.

 

• There are a variety of possible causes for fertility disorders, such as improper mating ratios and male body weight control.
• The fertility disorders is divided into four egg laying sections – early, peak, mid-lay, and late period.

 

 

There are a variety of possible causes for this, such as improper mating ratios and male body weight control.

1. EARLY EGG LAY HATCHES (26-28 WEEKS)————–

 

1. Insufficient number of active males.Four to five active males per 100 females at beginning of mating period are recommended.
   • Physiological Castration – Some normal appearing males at housing may have been “physiologically castrated” temporarily (or permanently) due to a very stressful event. Some possible causes are:
     1. Some individual males weigh below the critical “threshold” weight of 1.0 lbs. (455 gms) at 4 weeks of age.
     2. Erratic body weight development (zigzag), especially in the early and mid-growing period.
     3. Intestinal disease/toxins and subsequent negative effect on body weight development.
     4. Severe heat stress in late growing period (Or shortly after housing).

 

• Rough appearing and/or non-uniform males at housing. Flock may have an excess of culls, “crow-heads”, and small males. Some males may be permanently damaged. Some possible causes are:
  1. Average male body weights were below the suggested body weight goals for a prolonged period prior to housing.
  2. Insufficient floor and/or feeder space. This often occurs when grown with pullets at a high density less than 1.5 ft²/bird (more than 7 birds/m²).
  3. Disease or leg problems.

 

2. Male Aggression.Frightened females will remain on the slats or hide in the nests, resulting in reduced mating activity. No more than 4-5 active males per 100 females are recommended at the beginning of mating period. Some possible causes are:
   • Excessive male ratio at housing.
   • Average male weight in excess of suggested body weight goals at housing and continues to increase rapidly due to combination of overfeeding in male feeders and “stealing” from female feeders. This results in too many active males for the first few hens laying the first eggs. Note: to reduce stealing feed, it is suggested to (a) not dub the males, and (b) use a female-feeder grill opening that measures 2-1/4″ high by 1-3/4″ wide (57mm x 44 mm) or 2-1/2″ high hy 1-11/16″ wide (64 mm x 43 mm).

1. The male average weiqht is about normal at housing, but allowed to increase rapidly due to the same conditions mentioned above – With the same results.
2. Shortly after housing part of the males are not able to consume enough feed to maintain a “reasonable” weight gain and become very agitated. This occurs infrequently..

 

3. Eggs set before flock is 25 – 25-1/2 weeks old.Expected range of hatchability for eggs set between 24-25 weeks of flock age may be only 65-73% with a fertility Tange of 83-88% – when there are no other complicating factors.

 

 

 

1. PEAK EGG LAY HATCHES (29-39 WEEKS)

 

Peak Hatchability

 

Some possible causes for reduced fertility during this period are:

1. Insufficient Active Males or Male Aggression– The effects of either problem that occurred during the early mating period will generally (but not always) carry through the peak hatchability period.
2. Reduced Male Feed Consumption– This causes some males to “cull out” while other normal looking males stop semen production due to body weight loss. This can occur when no adjustment has been made in feed allotment for the males when they can no longer “steal” from the female feeders. The average male body weight may actually increase somewhat afterwards due to no energy being spent on sexual activity by these non-productive males – and, thus, goes toward growth.
3. Insufficient Water Consumption– This can especially occur with males fitted with specific drinkers with females on the slats.
4. Disease or Leg Problems.
5. Crowding (floor space)– High bird density in the hen house can affect male mating activity – as well as egg production. A minimum of 1.80 ft²/hen (no more than 6 hens/m²) is suggested in slat floor houses.
6. Male Feeder Space– Decreased hatch sometimes noticed with 12-13 males per pan feeder versus recommended 9-10 males. Some males may not be able to consume sufficient feed, especially later on with more “timid” spike males.

 

1. MID-EGG LAY HATCHES (40-50 WEEKS)

 

1. Reduced Male Feed Consumption.
2. Insufficient Water Consumption.
3. Disease or Leg Problems.
4. Crowding (floor space).
5. Male Feeder Space.Note: The causes for the above five catagories can be reviewed under “Peak Hatchability”
6. Insufficient Active Males – Usually need to “spike” with 2-3% younger males (2-3 males per 100 females) to achieve 8-1/2 – 9-1/2% total males in the flock. Possible causes of insufficient males during this period are:
   1. Overweight males – reduced mating ability.
   2. Bad feet/legs – often weight related.
   3. Ratio reduction – due to male mortality and normal culling.

 

7. Male Aggression – See previous suggested causes. The aggressive behavior is often established during the early mating period. One can usually find frightened hens, many with cut backs and flanks, remaining on the slats or hiding in the nests.
8. Excessive Feather Loss – Hens with tender backs avoid the males by staying on the slats or hiding in nests. This can be caused by a combination of factors such as low feed consumption, borderline or low energy and/or protein (amino acids) in the diet, cold weather (increased energy requirements), etc.
9. Hot Weather – Both fertility and egg production can suffer.

 

 

1. LATE EGG LAY HATCHES (50-65 WEEKS)

 

Due to age-related reduced mating activity, semen quantity and quality, etc. a minimum of 9 – 9-1/2% total males should be maintained to have 7-8% active males during this final mating period. Some possible causes of reduced fertility are:

1. Generally the same causes mentioned during the 40-50 week period carry through this period.
2. Overweight Hens – Female effect in fertility. This can especially be a problem in hot/humid weather.
3. Overweight Males – Although mentioned in previous sections, this cannot be over emphasized. The average male weight should not exceed 10 lbs (4.54 kg) – 9.71 lbs to 9.81 lbs (4.40 to 4.45 kg) is better! Individual males weighing more than 11-1/2 lbs (5.2 kg) will probably not be active at this age.

Hatchability and Fertility Goals (Weekly Average)
Age (wks)	% Hatch	% Fertility	Age (wks)	% Hatch	% Fertility
26	77	90	40	90	98
27	79	91	45	88	97
28	81	93	50	86	96
32	88	97	60	82	93
35	91	98	65	80	92

Suggested Mating Ratios——————–

 

 

1. As the average male body weight increases, more individual males will reach the sexual maturity threshold weight level, approximately +/-7.0 lbs.
2. At housing, mate 8-1/2 – 9-1/2% total males (8-1/2 – 9-1/2 males per 100 females.)
3. Provided that the averagemale body weight conforms to the male body weight goals, the suggested mating ratio should provide 4-5 active males per 100 females by 23-24 weeks of age. Note: Any more than this in the beginning can create male aggression.
4. The 8-1/2 – 9-1/2% total males should provide the recommended level of at least 7-8 active males per 100 females by 28 weeks of age.
5. Continue to maintain 7-8 active males throughout the remainder of the production period. This may require 9 – 9-1/2% total males after 50 weeks of age for optimum tail-end hatches.
6. Avoid having more than 10% males at any time to avoid possible mating interference.

NOTES:

1. Sometimes high early dead embryo mortality can be misinterpreted as low fertility.
2. Generally, lower fertiiity is correlated with actual increased early-dead embryo mortality – weak germ.

 

 

Commercial poultry breeding

The poultry industry breeds chickens destined for both commercial egg and meat production. Geneticists design special breeding programs to select birds with the best characteristics for egg or meat production. This selection process (called genetic selection or genetics) allows the industry to select strains of birds which are produced very efficiently in intensive housing systems. There are two main types of commercial chicken breeds: layers and meat (broiler) chickens.

Forming an egg

The hen releases a yolk with the egg cell in it from her ovary where it moves into the oviduct (egg production tube). When a cockerel and a hen are mated, the sperm cells from the cockerel fertilise the egg cell at the top of the oviduct (fertilisation is the joining of the female egg cell with the male sperm cell). The fertilised egg yolk then takes 23-26 hours to pass down the oviduct, during which time layers of egg white (albumen) are laid down. Two layers of egg membranes are then overlaid, and finally the egg shell. If an egg is not fertilised, it still goes through the same process in the oviduct but it will not develop into a chick.

The egg

Although the surface of the egg is covered with bacteria, it has its own protective mechanisms in place to prevent the bacteria spoiling the egg. These are:

• The egg cools off after it is laid and bacteria are less able to grow at lower temperatures.
• The shell is coated with a fine moist layer called the cuticle, which dries and protects the egg contents from invading bacteria. This also gives a pleasing appearance, or bloom, to the fresh egg.

Most eggs are laid in the morning. Eggs are collected as soon as possible after laying and placed in a cool room to help preserve their internal quality. Fertile eggs can be stored for up to 7 days at about 12-15^oC without loss of hatchability. Because of the danger of bacteria on egg shells going to the hatchery, all fertile eggs are fumigated on the farm or as soon as they arrive at the hatchery. Fumigation with the gas formaldehyde kills surface bacteria without damaging the fertilised ovum inside the egg.

Modern hatcheries use specialised equipment

Hatchery

The hatchery is a special building with controlled ventilation. It contains machines for holding and incubating large number of eggs. The hatchery is designed with hygiene in mind and is laid out so that there is little chance of any contaminating organisms travelling back from hatched chicks to eggs brought in later.

Stages of incubation

• First Stage of Incubation

The first stage lasts for 18 days and is called “setting”. During setting, the eggs are placed on special trays which can be tilted through 90 degrees, from side to side. The temperature and humidity of the air in the setter is controlled so that conditions inside each egg are suitable for the growth and development of the chick.

• Second Stage of Incubation

On the 18^th day, eggs are transferred to a different tray, which cannot be tilted, and placed in another machine called a “hatcher”. Eggs are transferred to hatchers so that hatching chicks do not contaminate other batches of eggs being incubated. The hatchers can then be thoroughly cleaned after every hatch. By the end of the 21^st day all chicks have hatched and are ready to be removed from the machine. They are taken to a special room and removed from the hatcher tray. They are then placed in chick boxes (usually up to 100 in a box) ready for delivery to a farm.

Candling of eggs

Candling of eggs is done after 5-8 days of incubation to examine for the presence of any infertile eggs. It is the easiest way to check on the development of the chicks inside the eggs.

Hatching chick

Chick sexing

Sexing allows separation of male and female chicks. This can be done by:

• Visual examination, (called vent sexing) either by checking the structures in the chick’s vent with the naked eye or by inspecting the internal sexual organs with a special lamp.
• Most breeds can now be sexed by checking the feather colour or the degree of growth of wing feathers. Genetic selection has been carried out to ensure that these differences between sexes are distinctive.

Layer chicks are always sexed, as the females are kept while the males are killed. Breeders are usually sexed, as a greater number of females to males are kept for breeding purposes. Meat chickens are normally left unsexed, as both sexes are usually reared together.

Other procedures

Day old chicks

Some vaccines can be administered in the hatchery. In meat chickens, all the required vaccines are administered in the hatchery before delivery to a farm. Beak trimming is sometimes carried out and in some breeds, the comb of the cockerels is trimmed (called dubbing). These procedures may seem cruel but they are carried out to prevent further injury later in life. Beak trimming is done in layer chicks to prevent pecking other birds, or cannibalism. Dubbing is done to prevent injuries to the comb which can result from fighting.

Chick requirements

The baby chick must be kept warm as it does not have the ability to maintain a constant body temperature. The chicks are transported in chick boxes which are designed to conserve heat while allowing air movement. The room where chicks are held in the hatchery and the truck which delivers them to the farm are also designed to keep the chicks both warm  (32-34^oC) and ventilated. There is enough food and water in the yolk to keep the chicks alive for about three days, but best results are obtained if they can eat and drink as soon as possible. When placed on the farm, they must be kept warm and have feed and water available at all times.

Reference-On Request