November 22, 2008

Animal behaviour and welfare: Poultry Part 3


Beak trimming: Chick handling: Lighting: Stocking density

By Dr Clive Dalton

Beak trimming
  • Beaks are trimmed to allow birds to eat but not peck each other. It's a very controversial practice and is high on the hit list of animal welfarists to be banned.
  • For day-old chicks in New Zealand the Code of Welfare No. 18 states not more than 2mm should be trimmed off the beak and for 10-day old chicks, not more than 3mm off the beak.
  • The Code says that further trimming should not be done unless there's a need to prevent cannibalism during the laying period. If properly done in the first place, further trimming should not be needed.
  • Care is needed to have the blade sharp, at the correct heat, and to remove the correct amount of beak with least stress to the birds.
  • Poor trimming can set a flock back by 2-3 weeks because of burnt tongues and nostrils that are slow to heal. This reduces feed and water intake, lowered body weight and production.
  • Studies showed that pecks from birds with trimmed beaks were largely ignored, compared to pecks from intact beaks. Trimmed birds showed higher levels of pecking but trimming did not change social ranking. Indeed the trimmed birds had to peck more to maintain their social rank.
  • In well-run cage systems where cannibalism is rare, beak trimming is not needed. The key point then is to fix the cause of cannibalism first, rather than see beak trimming as the solution.
Spectacles, polypeepers or blinkers
  • To avoid the need for beak trimming, commercial plastic spectacles called "polypeepers" were developed.
  • These are clipped on the beak of the bird so she cannot see forward to aim a peck at another bird.
  • Welfarists don't see them as a popular solution to pecking and peck damage, but studies have shown them to be effective, and birds had freer access to feed.
  • It takes a while for birds to get used to them and after about a month, birds studied were shown to produce more eggs for less feed and were much quieter than before.
  • Their use depends on convenience of fitting them and replacing losses. They seem to have gone out of fashion.
  • They are not recommended for use in New Zealand under normal circumstances.
Other mutilations
  • Dubbing where the wattles of birds are trimmed (cauterised) to stop injury by pecking from other birds is not recommended in the MAF Code of Welfare No.18.
  • Restricting the flight of birds by de-winging, pinioning, notching or tendon severing is considered to be cruel and not recommended by the MAF Code of Welfare No.18.
  • Toe trimming is sometimes necessary in some free-range situations and the MAF Code of Welfare No. 18 says that if performed should be limited to the nail of the toe only.
Early handling of chicks
  • The influence of early handling (before day 3) showed improved growth, more resistance to E.coli and an improved ability to cope with stress in later life.
  • It clearly seems worthwhile for attendants to deliberately handle birds gently, speaking to them quietly and doing some feeding from the hand.
  • This was called providing TGC - Tender, Gentle, Care.
  • Frequent visits by attendants in this early stage are important. However it's hard to imagine any of this behavioural conditioning being done in large commercial outfits.
  • As modern poultry are selected for high performance - there is constant pressure on nutritionists to come up with diets that would meet the needs of these birds, whether they are layers or broilers. The massive pressure to reduce the price of eggs and meat to the consumer has driven this.
  • Progress by nutritionists increases the challenge for the geneticists to find birds to exploit new diets, and vice versa. The incredible progress made has triggered plenty of behavioural problems and concern by welfarists.
  • Concern for Feed Conversion Efficiency (FCE) has put emphasis on reducing size, so the bird's appetite would normally have been affected. This has been dealt with by selecting for appetite and developing very highly concentrated diets.
  • Feed is the major cost (70-80%) in poultry production, and preventing waste has been important. Equipment designers have been challenged to stop birds wasting feed.
  • Flicking feed from their trough as they eat is common. It seems as if the birds are sorting through to find more attractive pellets.
  • Regular disturbance of the feed is done mechanically to provide some visual stimulus for the bird and maintain its interest.
  • After eating, bored birds will drink and then regurgitate their stomach contents back into the trough - called polydipsia. This creates great interest by the other cage members who eat it ravishingly. It's very wasteful of feed.
  • Both young and old birds soon learn to drink water from nipples that are triggered by a pecking action.
  • Modern poultry producers control the sexual development of laying birds and their subsequent egg production by modifying the lighting pattern. In general, birds are stimulated by increasing day length.
  • There is a whole range of patterns used for laying hens. They may be "step-up" or "step-down" and light intensity can be changed.
  • Birds seem to treat the longest dark period as night and the resumption of light as dawn. It seems that laying birds need no more than 17 hours of light for optimal production.

Stocking density

  • Stocking density is another factor of great concern to welfarists. It is a major factor along with Feed Conversion Efficiency in profit.
  • There are three main variables to consider in stocking density:
What is best for the bird?
  • What conditions give maximum output for the enterprise?
  • What colony size and space gives best economic return?
  • Studies show that decreased area/bird reduced egg production, lowered body weight and increased mortality. (Currently most caged laying birds live on an area the size of an A4 sheet of paper).
  • Increasing colony size depressed egg production, raised food consumption and increased mortality. These effects are independent and additive so you can get one or all of them at once.

  • Birds lose their feathers or moult when egg laying stops at the end of the season.
  • A new generation of feathers grows and pushes the old ones out taking about 8-12 weeks to complete.
  • This is seen as unproductive time in modern production systems so birds are not kept for a second season.
  • Some producers cull up to 25 % of birds before a second season as egg number/bird is 20% lower, egg size is increased but quality and shell texture is lower.
  • Breeders have selected strongly to reduce this moulting time - putting extra pressure on the bird to produce.
  • To await the long wait for a full moult, some producers induce a "forced moult" by reducing feed and water intake, and reducing light. Anti-ovulatory drugs can also be used as well as an unbalance of minerals in the diet.
  • This forced moult technique extends the birds normal pause which is the natural interval of 2-3 days after the hen has laid one egg/day for 6 days. There is debate as to whether an extended pause only is needed or whether a pause plus a moult is better.
  • There is little pecking between hens during the moult, but it increases during the recovery period, especially around feed hoppers. Studied showed that hens that pecked a lot also showed higher feed intake.
  • Hens have been shown to tolerate some force moulting regimes with no serious problems.
  • The MAF Code of Welfare No. 18 says that forced moulting should only be done on healthy hens, under close management scrutiny and conditions that will not cause stress. Methods that totally deprive hens of food and water for more than 48 hours must not be used.

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