Beak trimming is a common management practice in egg production used to control cannibalism and feather pecking – behaviours still not well understood nor completely controlled by breeding.
“Despite its effectiveness in curtailing these behaviours, trimming is often severely criticized,” says Karen Schwean-Lardner, a PhD candidate and manager of the Poultry Teaching and Research Unit in the Department of Animal and Poultry Science at the University of Saskatchewan. “It’s considered excessively painful mutilation by some and has been banned in a few European countries.”
Schwean-Lardner acknowledges that while severe trimming is an animal welfare concern, modern commonly used methods are moderate and exchange short-term pain for the prevention of a very large welfare concern – death due to cannibalism. “We recently finished a multi-year investigation of moderate beak trimming in an attempt to provide additional scientific evidence so that logical policy decisions can be made,” she says.
The research was funded by the Saskatchewan Egg Producers, the Canadian Poultry Research Council and the National Science and Engineering Research Council, and conducted with the support of Steinbach Hatchery and Feed in Steinbach Man., Clark Hy-Line Hatchery in Brandon, Man., and Pacific Pride Chicks in Abbotsford, B.C. Saskatchewan producers who allowed the researchers to assess their birds in terms of on-farm variability include Stan Fehr and family, Milden Colony and Sovereign Colony.
Tissue Involved
The outside of the beak is composed of a hardened keratinized layer that covers the surface, and below this layer (called the rhamphotheca) is an epidermis, which supplies material that forms an outermost harder surface, and below that, the dermis. “The dermis is a more sensitive tissue, and contains vascular tissue, as well as being well innervated with a number of types of nerve fibres,” notes Schwean-Lardner.
Beak trimming involves the removal of a portion the upper and lower beak of the bird, cutting through all tissues. The two most commonly used techniques are hot-blade trimming and infrared treatment. “Hot-blade trimming can be done at various ages from hatching to adult,” she says. “However, published literature has indicated that the trimming of adults can result in the formation of neuromas (overgrowths of nerve tissue), which can lead to chronic pain throughout the life of the bird.” Infrared, because of the expensive equipment required, is performed only at commercial hatcheries.
One of the research team’s goals was to determine when hot-blade trimming should be performed. “We examined behaviour and productivity of chicks trimmed at 0 days of age at a commercial hatchery, 10 days of age on-farm or 35 days of age on-farm, and compared these treatments to an untrimmed control group,” says Schwean-Lardner. “We found that beak trimming improved productivity in all age groups with respect to feed-to-feather cover. Trimming at 0 days of age resulted in the most rapid healing, with minimal or no impact on behaviour or body weight.”
Chicks trimmed at 35 days showed more regrowth of beak tissue, and Schwean-Lardner says this helps explain the higher feed intake of these birds compared to 0 or 10-day-old trimmed birds – but also provides the reason these birds sported poorer feather cover in comparison to birds trimmed at younger ages. “No neuroma formation was found in any of the beaks tested,” she notes, “indicating that chronic pain likely does not occur when hot-blading is performed at a young age.”
As an undergraduate research thesis, Misaki Cho studied whether there is a painless phase following hot-blade trimming. She indeed found, using behaviour and painkillers for a control, that for a two-hour period after trimming, behaviour was similar among all birds. This confirms earlier research, and Cho hypothesizes that natural pain-lessening opioids are released in the birds’ bodies following trimming. Tatiana Gabrush, as part of her master’s thesis, studied precision of day-old beak trimming. She determined that tissue removal could be accurately controlled in a commercial hatchery using either hot-blade trimming, but was slightly more difficult to control with infrared trimming.
“Overall, we found infrared treatment appeared to have advantages over hot-blade trimming,” says Schwean-Lardner. “With hot-blading, there are behavioural changes on the first day post-trim that indicate pain, where there are none with infrared – foraging activity and play behaviours such as running were similar in infrared treated birds and untrimmed birds.” Infrared treated birds also showed faster and more complete healing than those trimmed with a hot blade, Schwean-Lardner notes.
“As well, since there’s no open wound, there is no opportunity for infection,” she says. “Infrared also provided more uniform trimming and fewer minor beak defects.” Both methods provided effective control of cannibalism when at least 40 per cent of the beak was removed. “We observed the highest levels of aggression in untrimmed birds and those with 20 per cent tissue-reduced beaks,” says Schwean-Lardner.
Until genetics for laying hens with no propensity to feather peck or cannibalize are available, Schwean-Lardner believes beak trimming offers an effective method to reduce cannibalism. “Over the life of the bird, depending on which factors you consider, welfare of birds can be improved with beak trimming,” she says. “Our research supports the finding that moderate trimming effectively controls cannibalism, and for rapid healing and the least pain, trimming should be done at a very young age regardless of which technique is used.”
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