Your Poul­try

What chicken is that?

NZ Lifestyle Block - - Contents - WORDS SUE CLARKE

Abreed of poul­try (or any species) is a group which all bear sim­i­lar char­ac­ter­is­tics and which will breed true gen­er­a­tion af­ter gen­er­a­tion. This might mean they all have the same comb type, the same num­ber of toes, the same style of feath­er­ing and the same body shape. While peo­ple may call a pure breed chicken ‘pure’ be­cause its two par­ents looked to be the same breed, un­less ac­cu­rate records are kept go­ing back over sev­eral gen­er­a­tions (at least five) then you can never be sure that an­other breed was used, ei­ther by ac­ci­dent or in­tent, in ei­ther of the par­ents’ an­ces­tors.

A par­tic­u­lar breed will have what is known as a Breed Stan­dard, and this is true for dogs, cows, sheep and poul­try. This is where a group of fanciers have sat down and writ­ten a for­mal stan­dard to which all an­i­mals in that breed should con­form to.

From time to time they may ad­just the stan­dard to more ac­cu­rately de­scribe the type they would like the breed to con­form to. You only need to see pho­tos of a par­tic­u­lar breed of dog, cat or cow over the past 70 years to see how our idea of what a par­tic­u­lar breed should look like, or what fashion, and/or the show ring dic­tates it should be, has changed.

Some­times an­other breed may be added into the mix to make a slight change to it. This is a com­mon tech­nique breed­ers use when a new colour is de­sired. If a se­ri­ous fancier wants to de­velop a colour or breed which may ex­ist over­seas but not in NZ (be­cause it’s al­most im­pos­si­bly ex­pen­sive to im­port poul­try into NZ for biose­cu­rity rea­sons) then they will need to cre­ate a pop­u­la­tion of birds with the at­tribute, then breed sev­eral more gen­er­a­tions un­til they are cer­tain that the new phys­i­cal ap­pear­ance is breed­ing ‘true to type’.

Some breeds have fallen out of pop­u­lar­ity or even died out com­pletely. It may be pos­si­ble to use other breeds to recre­ate sim­i­lar-coloured and sim­i­lar-shaped birds that look like the orig­i­nals, but one of the con­se­quences of do­ing this is the small gene pool it cre­ates. To try to cre­ate a true-to-type bird means con­stant in­breed­ing which leads to a re­duc­tion in re­pro­duc­tive

pedi­gree “…the record of de­scent of an an­i­mal, show­ing it to be pure­bred.” pure­bred “…of or re­lat­ing to an an­i­mal, all of whose an­ces­tors de­rive over many gen­er­a­tions from a recog­nised breed.”

abil­ity, es­pe­cially if no se­lec­tion is done specif­i­cally for it (be­cause a breeder is usu­ally con­cen­trat­ing on colour or shape in­stead). Males be­come less fer­tile and fe­males lay fewer eggs, which may have very poor hatch­a­bil­ity due to a weak ger­mi­nal disc (the white spot on a yolk that con­tains the fe­male’s DNA con­tri­bu­tion) and the male’s in­abil­ity to fer­tilise them. This adds to the dif­fi­culty of pre­serv­ing the breed and in­evitably new blood from an­other but sim­i­lar breed may have to be added to im­prove the sur­vival rate.

Her­itage breeds

Pure­breds are tend­ing to be known nowa­days as her­itage breeds. These are poul­try breeds that have been in ex­is­tence since many were first es­tab­lished back in the late 1800s. Since then, many colours and va­ri­eties have been added to the orig­i­nal ba­sic breeds.

Pure breeds all have their own spe­cial char­ac­ter­is­tics, and it’s im­por­tant to pre­serve them for the fu­ture in case their par­tic­u­lar spe­cial­i­ties – for ex­am­ple, five toes, blue eggs, broad breasts, long legs, lack of brood­i­ness – are needed for fu­ture breed­ing de­vel­op­ments.

Sex-linked birds

Cer­tain char­ac­ter­is­tics, like the colour of the chick down and the rate of growth of the feath­ers from one day old, are gov­erned by genes. If those genes are car­ried on the sex chro­mo­somes you are able to dif­fer­en­ti­ate the sex of the chicks at hatch­ing pro­vided you cross two breeds which have the pure gene for the op­po­site con­di­tion. For ex­am­ple, you can cre­ate chicks that hatch with red­gold down (girls) and sil­ver-white down (boys), or it could be one sex feath­ers up fast (girls), with feath­er­ing be­gin­ning within a day of hatch­ing, and slow (boys), with no feath­er­ing ev­i­dent.

This is how com­mer­cial breed­ing com­pa­nies can eas­ily and cheaply sex newly-hatched chicks and only sell the pul­lets (fe­males) and ei­ther dis­pose of or fat­ten the males.

One of the most com­mon meth­ods uses Rhode Is­land Red roost­ers and Light Sus­sex hens. A pure­bred Rhode Is­land Red male car­ries the gold gene (ss) on his two sex chro­mo­somes, and he can only pass on gold colour­ing. A pure­bred Light Sus­sex hen car­ries the dom­i­nant gene for sil­ver (S-) and only has the one sex chro­mo­some, which means she can only pass on sil­ver colour­ing. Their chicks can ei­ther be (Ss) which would be sil­ver males with yel­low fluff, or (s-) which would be brown fe­males with gin­ger fluff (as they only have one sex chro­mo­some and the only gene from their dad is gold). Other sex-linked crosses in­clude ones where the fa­ther car­ries the gene for fast feather devel­op­ment (kk) which is char­ac­terised by early devel­op­ment along the wing edges at hatch­ing and the mother car­ries the gene for slow feather devel­op­ment (K-) on her one sex chro­mo­some, and the wing feath­ers have hardly erupted. This sex-linked cross is of­ten used in the broiler meat chicken in­dus­try to sex chicks that are then fat­tened us­ing dif­fer­ent feed regimes ac­cord­ing to their sex. Over­seas there are still some sex

linked crosses of pure breeds avail­able com­mer­cially. The Black Rock (a cross of a Rhode Is­land Red rooster over a Barred Plymouth Rock hen) uses the bar­ring gene for sex­ing. The bar­ring gene typ­i­cally pro­duces chicks with or without a white spot on their heads.

The ‘Golden Comet’ is an­other sex linked cross of a Rhode Is­land Red rooster over a White Leghorn hen which uses the gold and sil­ver gene.

While any­body with these breeds could produce chicks which are able to be sexed at hatch­ing, com­mer­cially-pro­duced birds have been de­vel­oped from strains of the breeds that have been se­lected for their egg pro­duc­tion and type, as well as the par­ents also breed­ing true for the de­sired down colour of the chicks. It has taken decades of highly-funded breed­ing pro­grammes to produce well­rounded birds, and ac­cess to good qual­ity birds to start with.

Hy­brids

Nowa­days when we talk about ‘chick­ens’, we’re of­ten re­fer­ring to the brown hy­brid birds used on com­mer­cial farms.

Hy­brid birds have been de­vel­oped over many gen­er­a­tions from pure breeds (eg, Leghorn) but are so ad­vanced, they are now a mix usu­ally just of ‘lines’ de­noted by num­bers or let­ters. Some hy­brids are ac­tu­ally just pro­duced by cross­ing very pro­duc­tive strains of one breed.

The two in­ter­na­tional com­pa­nies that sup­ply hy­brids in NZ are Shaver and Hy­line which sell day-old pul­lets.

Layer hy­brids

There are many White Leghorn-type com­mer­cial hy­brids on the mar­ket around the world, de­vel­oped by dif­fer­ent breed­ing com­pa­nies and called by dif­fer­ent names or num­bers. The Shaver 288 was a White Leghorn cross that used to be avail­able in NZ up un­til about 10 years ago. Hy­line also had a strain cross based on the White Leghorn, known as the W98. Nei­ther of these birds is now avail­able. Some­time in the 1990s, the NZ pub­lic be­gan to pre­fer to eat brown-shelled eggs and so now all com­mer­cial layer hens are brown- feath­ered and lay brown eggs. The white hy­brids are still avail­able over­seas where white eggs are pre­ferred by con­sumers. The brown-feath­ered hy­brids avail­able in NZ to­day are called the Hy­line Brown and the Shaver Brown. Both are light-weight, feed-ef­fi­cient birds which lay brown- shelled eggs and have de­scended from slightly dif­fer­ent crosses of both white and brown breeds over the years. The com­pa­nies that sup­ply these birds hatch mil­lions of eggs a year in NZ, and can sex the chicks just by look­ing at the colour of their down. The fa­ther car­ries the gold gene (ss) which he passes on to his daugh­ters, which hatch with gin­ger fluff and grow on to have brown adult feath­ers. The mother is a small, mainly white bird that lays brown eggs and car­ries the sil­ver gene (S-) on her one sex chro­mo­some. Male chicks are (Ss), with one gene from each par­ent, have yel­low fluff and mainly white feath­ers with brown shoul­ders when an adult.

Meat hy­brids

Meat chick­ens are usu­ally all white­feath­ered and have also been de­vel­oped over many years. The com­mer­cial com­pa­nies that cre­ated these hy­brids orig­i­nally used strain crosses of dif­fer­ent heavy breeds such as Cor­nish Game, Light Sus­sex and White Plymouth Rocks.

Male and fe­male chicks of this hy­brid fat­ten at dif­fer­ent rates, so the com­pa­nies used a nat­u­rally-oc­cur­ring feath­er­ing gene to en­sure a cheap and easy method of sex­ing. They first had to make sure the two par­ents were ‘pure’ for ei­ther slow or fast feath­er­ing, which is known to be in­her­ited on the sex chro­mo­some. This method can only be done with cer­tainty in the first day or two af­ter hatch­ing.

Barn­yard ‘spe­cials’

These birds can be any breed, layer, meat, heavy, light, ban­tam and are what you’ll see in most back­yards. Peo­ple on poul­try Face­book pages and other places on­line of­ten post im­ages of very hand­some birds ask­ing what breed they are, but usu­ally they can­not be as­signed to any one breed be­cause they are crosses of crosses. You can take a Shaver or Hy­line hen and cross it with a cross-breed rooster and cre­ate hens which are ex­cel­lent lay­ers. They may even look like their brown­feath­ered mother. How­ever these can­not be sold as Shavers or Hy­lines as they can never re­peat the pro­duc­tiv­ity of the par­ents of the orig­i­nal hy­brid, and the com­pany names are trade­marked.

Se­bright ban­tam.

White Silkie.

Pol­ish rooster.

IN SLOW FEATH­ER­ING, both pri­maries and sec­on­daries are short, the same length and un­opened.

Fast feath­er­ing day old chick. Sec­on­daries Pri­maries IN FAST FEATH­ER­ING, pri­maries erupt on the edge of the wing and are usu­ally at the ‘paint­brush’ stage of open­ing, and are much longer than the sec­on­daries that erupt fur­ther back on the wing. Sec­on­daries Slow feath­er­ing day old wing. Pri­maries

Male and fe­male chicks can be sorted by colour at hatch­ing if it’s pos­si­ble to use sex-linked genes.

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