The strange fam­ily mat­ters of the com­mon chicken

The chicken is the most com­mon bird in the world, and the most com­mon breed has the most com­pli­cated fam­ily of all.

NZ Lifestyle Block - - Contents - WORDS SUE CLARKE

Chick­ens are the most com­mon bird in the world and they have a com­pli­cated fam­ily tree.

The types of poul­try and the ter­mi­nol­ogy used by those in the chicken world can be con­fus­ing, es­pe­cially if you’re new to it.

What you re­ally want to know is what types are avail­able and which ones would be best for your sit­u­a­tion. But you may then start to won­der why this fam­ily of an­i­mals is so dif­fer­ent, and what is be­hind the var­i­ous breeds.

The do­mes­ti­cated fowl is of­fi­cially, sci­en­tif­i­cally, known as Gal­lus gal­lus. All the breeds in the world are be­lieved to orig­i­nate from the Red Jun­gle Fowl which was do­mes­ti­cated about 5000 years ago.

How­ever, in 2008, ge­netic re­search of the skin colour of chick­ens showed there was also an­other species mixed up in this chicken soup, prob­a­bly the closely-re­lated Grey Jun­gle­fowl which car­ries the genes for yel­low skin that is com­mon in the do­mes­tic birds we see to­day.

What the terms mean Poul­try: can re­fer to the fowl species – the do­mes­tic chicks, pul­lets and adults we have in our flocks – but can also en­com­pass the duck, goose, turkey and guinea fowl species when talk­ing gen­er­ally.

Chicken: tech­ni­cally refers to the youngng fowl, but is to­day also com­monly used as a generic term to cover all age groups.s. Some also ar­gue it should only be used to re­fer to end-prod­uct, eg chicken is a meat, eat, while poul­try is the cor­rect term for fowl wl that is liv­ing.

Hen: an adult fe­male fowl, usu­ally over one year old and in her sec­ond lay­ing sea­son.

Pul­let: a ju­ve­nile fe­male fowl from hatch­ing to her first lay­ing sea­son, which can vary from the start of phys­i­cal al ma­tu­rity to af­ter her first year.

Cock/rooster: a ma­ture male usu­al­lyy over one year old.

Cock­erel: a ju­ve­nile male from hatch­ing un­til ma­tu­rity at around one year old, which can vary from start of phys­i­cal ma­tu­rity or af­ter first year. Her­itage breeds* These are of­ten classed as the ‘pure breeds’, as out­lined in the of­fi­cial breed stan­dards which is up­dated from time to time as new colour/forms are sta­bilised.

Breeds can be grouped into birds of sim­i­lar size. *NB some breeds listed are not cur­rently present in NZ or do not have full recog­ni­tion by the NZ Poul­try As­so­ci­a­tion; many have a range of colours and feather pat­terns within the stan­dard type. Heavy Breeds as per NZ Poul­try Stan­dards Most of the heavy breeds were de­vel­oped in Amer­ica and the UK and lay buff to brown eggs. The state­ment that birds which have red ear lobes lay brown eggs is of­ten quoted but ‘brown’ can vary from rich brown to pale beige. Aus­tralorp, Barn­evelder, Brahma, Chi­nese Lang­shan, Croad Lang­shan, Cochin, Dork­ing, Faverolle, Friz­zle, Maran, North Hol­land Blue, New Hamp­shire Red, Or­p­ing­ton, Ply­mouth Rock, Rhode Is­land, Sus­sex, Wyan­dotte Hard feathered breeds This in­cludes game birds, some of which may have a ban­tam ver­sion. Old English Game, Mod­ern Game, In­dian Game, Malay, Asil

Light breeds as per NZ Poul­try Stan­dards Many of these are of Mediter­ranean ori­gin, although the Silkie is of Asian ori­gin. Most lay white eggs, but some can tend to cream, and the Arau­cana lays blue eggs. Most light breeds have white ear lobes, but those of the Silkie can be turquoise blue or mul­berry (dark red). An­cona, An­dalu­sian, Arau­cana, Campine, Ham­burg, Houdan, Leg­bar, Leghorn, Mi­norca, Pol­ish, Si­cil­ian But­ter­cup, Span­ish, Silkie, Wel­sum­mer Ban­tams These are smaller ver­sions of many of the stan­dard breeds, in­clud­ing the Game breeds, but there are also some breeds which are ‘true ban­tams’ with no larger ver­sions True Ban­tams as per NZ Poul­try Stan­dards Ja­panese, Pekin, Rosec­omb, Se­bright, Bel­gian Bearded, Booted, Dutch The most com­mon birds in the world The world’s av­er­age stock of chick­ens is al­most 19 bil­lion ac­cord­ing to statis­tics from the UN’S Food and Agri­cul­ture Or­gan­i­sa­tion in 2011, and most of them are com­mer­cial hy­brids.

These are the re­sult of sta­bilised crosses of var­i­ous strains and breeds which over the years have been bred to pro­duce a bird with con­sis­tent type and per­for­mance for eco­nomic pur­poses.

They are the re­sult of cross­ing two par­ents of dif­fer­ing strains and this means they can­not be bred ‘true’. For ex­am­ple, if you cross a Shaver Brown hen with a Shaver Brown rooster, you won’t get chicks that show the same re­li­able traits (eg high lay­ing) as their par­ents. This is be­cause breed­ing stock is care­fully con­trolled by the com­pa­nies which sup­ply these birds to com­mer­cial poul­try farm­ers, to pre­vent theft of their care­fully-cre­ated ‘brand’. Fran­chised hatch­eries pay a roy­alty per chick hatched back to the de­vel­oper – the two big brands in NZ are Shaver and Hy­line – which funds on­go­ing de­vel­op­ment work and dis­tri­bu­tion world­wide. In New Zealand there are two com­mer­cial layer strains and two com­mer­cial meat strains avail­able. Lay­ers: Hy­line Brown, Shaver Brown Meat: Cobb White, Ross White These com­mer­cial birds are pro­duced un­der strict fran­chise sit­u­a­tions. A hatch­ery will im­port the breed­ing ‘stock’ as fer­tile eggs which are then hatched and reared un­der quar­an­tine as ‘grand­par­ents’. Their chicks are then cross bred to be­come ‘par­ents’, and their cross­bred chicks be­come our lay­ing hens and roast din­ners.

hy­brids do not breed ‘true’

The cre­ation of a layer hen The Grand­par­ent bird may be bred from up to four dif­fer­ent strains and each one con­trib­utes a dif­fer­ent qual­ity to the Par­ent bird. If the even­tual off­spring was to be a Shaver Brown or a Hy­line Brown then the strains pro­duc­ing the par­ent roost­ers may well carry traits such as: • brown feath­ers from breeds or strains, de­vel­oped over many years to be birds which carry brown feath­er­ing; • con­sis­tently lay­ing qual­ity brown eggs with good in­ter­nal egg qual­ity and shell strength; • good live­abil­ity (able to sur­vive the con­di­tions); • a docile tem­per­a­ment; • good feed con­ver­sion, ef­fi­ciently con­vert­ing feed to eggs.

One set of Grand­par­ent birds (we’ll call them A and B) could be from the same strain or dif­fer­ing strains. Only the male chicks are kept for breed­ing.

Grand­par­ents C and D will have been se­lected slightly dif­fer­ently and will sup­ply the fe­male chicks used for breed­ing.

These will have traits for things like: • good re­pro­duc­tive qual­i­ties; • egg num­bers; • in­ter­nal and ex­ter­nal egg qual­ity; • small body size; • po­ten­tial to lay good-sized eggs on min­i­mal feed eaten; • the abil­ity to have long clutch sizes, eg eggs laid on con­sec­u­tive days; • lack of broody ten­den­cies; • a docile tem­per­a­ment; • the abil­ity to lay over a long sea­son, pos­si­bly up to 18 months, be­fore stop­ping to moult.

These hens will also have genes for brown eggs. These are typ­i­cally only found in heavy breeds which lay fewer eggs, so the an­ces­try line for a small, white­feath­ered, brown egg-lay­ing breed needs to be de­vel­oped first.

The re­sults of the mat­ings of Grand­par­ents A&B and C&D will pro­duce male chicks with spe­cific traits and fe­male chicks with dif­fer­ent ones. When these Par­ents are mated to­gether, each will in­tro­duce a set of traits which com­bines to pro­duce a hy­brid chick that is bet­ter than either of its par­ents.

Al­most all of to­day’s com­mer­cial hy­brids are able to be sexed eas­ily at hatch­ing either by down colour or by wing feather de­vel­op­ment. In the case of the Hy­line and Shaver Browns, the males have yel­low down, while the girls are brown.

The abil­ity to de­ter­mine the sex of these chicks on hatch­ing just by look­ing at their down colour means much cheaper pro­duc­tion costs. In the past, these com­pa­nies used pro­fes­sional vent sex­ers which ex­am­ined each bird to de­ter­mine whether it was male or fe­male, highly spe­cial­ist work that is not ac­cu­rate. Us­ing ge­net­ics means their cus­tomers can be guar­an­teed (99% or higher) that what they buy are pul­lets. Hatch­eries also al­ways sup­ply more chicks than they are paid for to cover sex­ing er­rors and deaths in trans­port.

The cre­ation of the meat bird The Ross and the Cobb are meat birds (broil­ers) pro­duced by dif­fer­ent com­pa­nies. A very sim­i­lar se­lec­tion process is used as for layer hens, with each par­ent bring­ing its own set of traits to the fi­nal chick.

The male line se­lec­tion of traits puts more em­pha­sis in se­lect­ing breed­ing lines de­vel­oped for: • its abil­ity to grow fast • the di­men­sions and pro­por­tion of meat to the breast and thighs

• con­ver­sion of the least feed into the most meat • docil­ity • white feath­er­ing so coloured feather stubs do not show on the car­case

• re­pro­duc­tive traits, like fer­til­ity

Great grand­par­ent gen­er­a­tions may be se­lected from the very top birds from trial flocks of thou­sands of birds. These birds are x-rayed to check on leg de­vel­op­ment, to en­sure car­ti­lage is form­ing cor­rectly, and that the skele­tal frame is able to carry the weight of this fast-grow­ing bird.

The fe­male par­ent of a meat bird needs to be able to lay a rea­son­able num­ber of eggs. She needs to be lay­ing large eggs quickly, which will then pro­duce big­ger day-old chicks, and have some of the growth and meat char­ac­ter­is­tics of her mate.

She may lay only half the num­ber of eggs that her hy­brid lay­ing hen coun­ter­part pro­duces, so to pro­duce lots of broiler chicks eco­nom­i­cally she will need to have the po­ten­tial to lay more eggs than the meat sire line and their hatch­a­bil­ity needs to be high as well.

The com­bi­na­tion of the two par­ent lines pro­duces a good num­ber of fast-grow­ing chicks, up to 150 per hen in her lay­ing sea­son. The breed­ers are usu­ally culled at 64 weeks of age af­ter a 40 week lay­ing pe­riod.

Care­ful at­ten­tion is paid to feed amounts and weight gains for these spe­cially se­lected meat par­ents. Even so they will prob­a­bly lay more eggs and grow far more ef­fi­ciently than some of the large her­itage breeds from which they were de­vel­oped.

It’s a dif­fi­cult process be­cause ge­netic se­lec­tion for growth/meat is coun­ter­pro­duc­tive to re­pro­duc­tion traits, eg the big­ger the bird, the less eggs it will lay. The same ap­plies in meat an­i­mals such as cat­tle, where se­lec­tion for milk pro­duc­tion in cows, and the abil­ity to get in calf early and an­nu­ally, is the op­po­site to that of beef cat­tle which grow fast and

Meat birds look very dif­fer­ent to lay­ers, but sim­i­lar pro­cesses are used to get a bird that grows big and fast.

mus­cu­lar, pro­duce less milk, and are later to ma­ture.

Once chicks are hatched, it’s of­ten im­por­tant to sep­a­rate the boys from the girls. You al­ways want your KFC drum­sticks to be same size, and male and fe­male meat chick­ens grow at dif­fer­ent rates, so are of­ten reared sep­a­rately so a farmer can guar­an­tee a con­sis­tent size of bird.

Brown Saver.

Ja­panese ban­tam.


Sil­ver Laced Wyan­dotte.

Old English Game hen.

Red Jun­gle Fowl.

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