Structure and dynamics of australia's commercial poultry and ratite industries

1.6 Typical Structure of Chicken Meat Flocks

Great Grand Parent (GGP) and Grand Parent (GP) Flocks

In 2008, there were an estimated 6.5 to 7 million adult breeder birds (Meat GGPs, GPs and Parents) in Australia.

Since 2005, the importance of these elite flocks as repositories for overseas breeding stock has increased. The number of GP’s and parent breeders exported out of Australia is expected to increase significantly over the next few years. This is particularly so with the recent acquisition of a PAQ facility and GGP and GP facilities by a large international company. The increase is also likely now that two of the three Australian producers of broiler breeder stock are independent of the chicken meat producers. There are currently no specific health issues affecting Australian breeding stock, unlike the health issues associated with J-Leucosis in the early 1990s. All strains of breeders, however, have experienced increased difficulties with male fertility and hatchability under increased husbandry requirements.

After importation through either Torrens Island or private quarantine facilities, the small GGP flocks are maintained in facilities under a high level of husbandry and biosecurity. Typically, in the GGP import there will be one male line and two female lines. Within each of these lines there are both male and female lines. Genetic selection for growth and meat yield in the broiler has put significant pressure for reproductive performance on the meat breeder. Hence, while the male line is essentially selected for broiler traits, the female lines still maintain some selection pressures for egg production and hatchability. Despite this, there is still the need for specialised husbandry practices with chicken meat lines in order to achieve reasonable reproductive performance. Because of the high value of individual birds, facility quality and husbandry inputs are optimal. Vaccinations are usually typical of what all levels of breeder stock obtain but in some cases certain vaccines like those for Mycoplasma may be excluded to assist avian disease serological monitoring programs where vaccination could make differential from wild type infection difficult.

Where limited exports occur with breeding stock, this may also restrict the ability to use certain vaccines. While vaccination for Newcastle disease (NDV) is obligatory in most states in Australia, some companies are seeking to implement strict biosecurity practices at their GGP facilities. This stock is also usually maintained under tight physical security to avoid theft of valuable genetic material and when flocks are depopulated they are invariably slaughtered under strict agreements.

Where imports are not regular, GGP birds must be generated from existing GGP stock. The disease status of these GGP birds is critical as the multiplier effect from GGP to GP to Parent Breeder to progeny is substantial. Similarly, undesirable genetic traits in individual birds can have a major impact.

GP flocks are usually located in the same locality as the GGP and they are maintained under similar husbandry conditions. There are two GGP facilities in New South Wales, one in South Australia and one in Victoria.

A designated hatchery is used for the hatching of parent breeders (PBs). These PBs are the source of broiler progeny and are transported as day olds to the various PB rearer farms that are located in most states in Australia. This may be to company farms or those of other integrated chicken meat companies.

While all feed supplied to the mainstream chicken meat companies is heat treated pellet feed, there is some interest in using vegetable based protein ration for GGP and GP flocks based on concerns about salmonella in meat and bone meal; however, sterility may be affected more by the milling process than the source of the protein.

Parent Breeders (PBs)

Physical treatment of birds may include trimming of the back toe of males at one day of age and beak tipping of male and females at around five days of age. Females are less commonly beak-tipped as the incidence of cannibalism and egg picking has been reduced by improved facilitation and management. Males are still commonly beak-trimmed to reduce the amount of neck scruffing damage done to females during mating. Back toe removal in the male is to similarly avoid damage to the female during mating.

The vaccination program in PBs is quite extensive. The value of stock justifies this investment against disease and to boost maternally transferred antibody levels to protect the young broiler chick against immunosuppressive disease such as Infectious Bursal Disease (IBD). More recently, to avoid loss of uniformity during rearing due to challenges with coccidiosis, most breeder rearing is done using a coccidial vaccination program. Killed NDV vaccination is not mandatory in broiler breeders but live NDV (V4) with monitoring serology must be undertaken. A new imported coccidial vaccine has been introduced onto the market and now industry may choose between using the imported or locally produced product. Salmonella vaccination is undertaken by some operators using autogenous killed products.

PBs can be reared either in “day old to death” facilities or in designated rearing facilities where birds are moved to designated breeder facilities at around 20 weeks of age, referred to as “rear and move”. Since 2005, the latter is becoming more common due to changes in production shed design. New designs use slats and automated nest box systems rather than the older style deep litter sheds with manual collect nest boxes. Each approach has its advantages and the choice is influenced by available company facilities, time requirements, disease control programs and available staffing. Shed designs are varied but include the three major types which include natural ventilation, fan-assisted and controlled environment (CE). All housing is based on floor rearing referred to as the barn or deep litter system. This is distinct from the trend in commercial layers for colony cage rearing. Preferably young birds are reared in light controlled sheds which can be blacked out in the newer controlled environment type sheds or dimmed in the case of the older style fan-assisted sheds. All new shedding has automatic nest box collection systems with partially slatted floors in the sheds. While these systems benefit from a lower labour cost and greater hatching egg recovery, there are some losses in hatching egg fertility.

Ambient light control is required to reduce the birds’ activity while being reared on significantly controlled feed intakes. PBs have the genetic growth potential of broilers and if allowed to eat ad lib, the males will approach weights of 3.0 kilograms at 7 weeks of age and the females 2.3 kilograms. For successful reproductive performance these weights need to be reached at closer to 20 weeks of age. Such strict weight control necessitates ambient light control of around 10 to 12 hours per day, low density feeds and automated feeder systems that allow rapid distribution of prescribed quantities of feed to all birds almost simultaneously. Compared to ad lib feeding times with broilers and commercial layers, feed times for rearer breeders are between 30 and 120 minutes. Under these specific husbandry conditions, the manager must also ensure that the young breeders maintain the correct body weight to age profiles, correct conformation and, most importantly, flock uniformity. The weekly weighing of a sample population of birds is required to allow quantitative feed adjustments and the grading of birds into various pens containing particular weight profiles is common.

From around 20 weeks of age the light intensity and period for PBs are increased in order to stimulate laying. In a rear and move system, the PBs are moved across to the production (laying) farm at around 21 weeks of age. Light hours are further increased as are the feed quantities (up to around 16 to 17 hours light at 27 weeks of age or around 70% production). Peak production of around 85% hen day production is achieved at around 30 weeks and on a peak feed intake of around 155 to 175 grams (this compares to commercial layers which peak around 95% on 110 grams of feed). The male to female ratio is around eight to ten per cent males and a female breeder hen will produce around 150 fertile hatching eggs by 64 weeks of age. At this age the flocks are usually depopulated. As in rearing, the monitoring of body weights and maintaining the correct body weight profile against net nutrient intake is critical if a producer is to achieve optimal breeder performance and hatchability.

Sheds of breeder farms usually contain between 7000 to 10 000 birds and each single age farm unit has between 20 000 to 40 000 PBs. The actual farm size is dependent on the company’s weekly hatching egg requirement. As the hatchability of fertile eggs declines rapidly after eggs have been stored in a cool room for ten days, it is critical that production outputs match hatching egg requirements. This again emphasises the importance of planning in the chicken meat industry where shortages or over production can be economically damaging.

Breeder farms are generally located away from broiler grow outs and other types of poultry. Since 2006, a number of new broiler breeder facilities have been built in South Australia, Queensland and Victoria. Some operations, as a consequence of historical growth, still have breeder facilities located regionally near broiler farms or hatcheries. New expansions are generally undertaken on breeder farm complexes where there may be several rearing and breeding farms located within eyesight of each other but usually at least 500 metres distance. These complexes are multi-age.

The majority of breeder farms are maintained under biosecure conditions which include perimeter fences, shower on facilities and mechanisms by which hatching eggs and (in some cases) feed and other services can interact with the farm without entering the farm proper. Water supplies are not uncommonly derived from non-main water supplies because of the isolation of some of these farms. Underground or surface water is used as an alternative, the later sanitised using chlorine or chlorine dioxide. Feed is always processed pelleted feed and delivered in sealed transport vehicles. Inside sheds, feed delivery systems are both trough or pan feeders and the majority of farms have nipple drinkers.

Egg collection systems are progressively moving away from the traditional single or double tiered manual collect nest box to automated egg collection systems. While the cost of labour and its availability is the driving force here, aspects related to occupational health and safety (OH&S) are also considerations. Such systems consist of a percentage of the floor being slatted with the rest consisting of deep litter. Nest boxes are either of the single hole or colony nest type with an automated egg belt running back into the centralised collection point in a partitioned area at the end of the shed. Variations on this include the inter connection of a number of sheds with anacondas (egg conveyors) as seen in commercial egg laying farms.

Egg collection costs range from around four to six cents per egg for manual collection systems, to two cents for automated systems. Manual floor collections are still generally required for the small number of eggs that are laid on the floor and / or slats and this is undertaken between eight to four times a day depending on the production time cycle. Nest box or egg belt collection occurs three to four times a day. Recovery of useable settable eggs is around 95% with the remaining rejects and double-yolkers being utilised in a number of ways, including egg pulp, through the commercial laying company grading and processing plants.

There are also new style broiler breeder facilities which are certified to European standards with colony cages. These are the most modern type of PB facilities developed in Europe.

Breeder hens are depopulated around 64 weeks of age and are taken to either company processing plants or to specific poultry processing plants that specialise in processing spent breeder and layer hens. Recently, the trend has been for the owners of spent broiler breeder hens to slaughter birds, rather than independent processors. The meat from these birds is used in further processed products such as chicken loaf and soups.

Transport contractors involved in spent hens movements pose a potential biosecurity risk.