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October 1, 2022 | by Sam Shafer
In a recent study, poultry scientists investigated the best way for manually catching chickens in a production setting. The two main ways for manually catching a chicken are the one-legged catch and the two-legged catch. The researchers examined chickens after catching to see how the two methods compare when it comes to potential injuries and effects on chicken behavior.
As the researchers report in Poultry ScienceⓇ, the actual number of grasped legs is not the biggest factor in injury occurrence. Instead, their study suggests careful handling and effective worker training may make the biggest difference.
Based on welfare research in the early 1990s, it has long been recommended that workers catch chickens by grasping them by two legs while the birds are in an upright position. The goal with this method is to reduce bird stress and injuries caused by the bird flapping its wings and trying to free itself. This kind of agitation can lead to severe injuries if the bird attempts to escape or strikes a cage during the loading process.
For the new study, the Germany-based research team looked at the effects of catching in more detail by comparing videos of catching and loading with examination of the chickens being handled.
For this experiment, catchers were randomly chosen from groups of employees experienced in catching chickens at a production facility. Broiler chickens were examined before catching by a team of veterinarians. For the different groups of chickens, the catchers would first catch birds using one method and then switch and catch the birds using the other method. Caught chickens were loaded into metal cages at a density of 29/birds per crate. Videos were taken throughout the process. Chickens were also studied before and after catching to determine their level of fearfulness toward people, for example, how much distance they put between themselves and humans reaching into their cages.
Using the videos, the scientists tracked incidence of agitation from the birds during catching and potentially damaging handling by the catchers (such as times when birds were dropped into crates).
The first striking difference was in loading time. Chickens caught with the one-legged method took less than half the time to load as the chickens caught with the two-legged method. The team found it was rare for a chicken to wing flap during grasping itself; instead, birds flapped a lot (84 percent of the time) when carried in the air, and this happened more often with the one-legged catch. The chickens were less likely to wing flap when carried in a hand with other birds (“neighbors”).
Two handling techniques made a difference in wing flapping regardless of how many legs were grasped. First, it helped to catch the bird and then let the bird stand still for a few seconds before transport. Second, catchers reduced wing flapping in the air by catching birds higher up on the leg, close to the feathers.
About 8 percent of the chickens struck the cage during the loading process, and these tended to be the lighter birds. When the researchers examined birds for hematomas (bruising) they found hematomas more common in birds loaded into bottom crates, versus high or middle crates. Increased wing flapping also led to more hematomas.
The other common injury was epiphysiolysis, a separation of the bones at the shoulder. Less than one percent of the chickens were diagnosed with epiphysiolysis of the humerus, and this injury was more common after the one-legged catch. The birds most prone to epiphysiolysis were also: more avoidant of catchers, took longer to catch and were loaded into bottom crates.
Overall, the two-legged method had advantages but took far longer. To make the biggest difference in chicken health and welfare, the scientists say the key is to have a very secure grasp on the chicken. Going forward, the scientists recommend further study of the crating process itself.
What does this study mean for producers?
Categories: Interpretive Summary