한국형 한협 육계의 행동 특성과 성장성에 미치는 Litter Type과 Gender의 영향

For this experiment, we raised 10-day-old chicks (n=416) for Korean Hanhyup broiler (HANHYUP No.3). The chicks were separated into 4 different pens. Twenty-five male and 28 female chicks were put on 2 pens of sawdust, and 2 pens of rice husks. Chicks were randomly assigned in a 2 × 2 factorial experiment and 4 treatment combination by type of litter and gender. All the walls of each pen were solid and 0.7 m high. Each pen had an overhead brooder and a circular free. The feeding trial started at d 10 and finished at d 70 of age for 60 days. The temperature and relative humidity were kept at 30℃ and 50%, respectively. According to the feeding standards (NIAS; National Institute of Animal Science, 2007) flocks were given a free access to the feed. For an 8-week period, chickens were kept under 16 hours of light per day (16L: 8D).

We recorded behaviors for 12 consecutive hours from the 1^st to the 8^th weeks of age. To examine the Korean HANHYUP broiler’s behavior, we evaluated the time spent for standing, sitting, and walking and the frequency of drinking, feeding, preening, dust bathing, flapping, aggressive pecking, and pecking (Table 1). Overhead camera generated the top view of poultry. The top-view camera was placed at the height of 1.7 m, above the center of each pen. The CCTV camera captured the behavior images (IR LED Camera; APD-7070V, Sony, Fig. 1).

Fig. 1. Analysis progress.

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Two methods of time sampling were involved with measuring what is happening at particular moments (instantaneous sampling) or recording whether or not a given event has occurred within a given period (one zero) (Martin et al., 2007). chicken's behavior during the starter (1 to 4 weeks) and the finisher (5 to 8 weeks) periods was compared to see the changes in each behavior as the chickens matured.

Our analysis was performed with SAS software (SAS, 2003) for independent sample T-test. Significant difference (P<0.05) was used to analyze the difference between types of litter (sawdust and rice husks) and gender (male and female). The probability value of 0.05 was considered as significant.

Table 2 and 3 are the summaries on the effects of types of litter and gender on behavior. The percentage of standing time was shown similarly in both early and late periods. In type of litter, males were analyzed to be higher in rice husks than the other, whereas females higher in sawdust than the other. In contrast to the standing behavior, sitting time appeared higher in sawdust than in males, whereas appeared higher in rice husks than in females. Sitting time means rest and inactivity, but the types of litter coming into contact with skin can cause disease in the parts of body being in contact with litter and this was worsened as a result of prolonged sitting time and indicates a low level of welfare (Shields et al., 2004).

In the early and late part of behavior (drinking, feeding, preening, dust bathing, and pecking flapping), there was no gender difference, but sawdust appeared higher than the rice husks in the effects of type of litter (Table 2 and 3). This was consistent with the findings reported by Song (1996) that the feeding behavior of males are 4 to 5 times faster than that of the females who spent longer time in feeding in one day. Feed efficiency and feed ratio were higher in males than in females (Marks, 1985). Most of the poultry rested after preening behavior. Preening behavior, which is a part of grooming behavior can be motivated by internal and external stimuli to maintain the body surface (Vezzoli et al., 2015). Therefore, in this experiment, the preening and dust bathing behaviors, which are a kind of resting behaviors are higher in sawdust than in rice husks.

Aggressive pecking and pecking occurred incrementally in the ‘rice husks’ pens compared to the ‘sawdust’ pens (P<0.05, Table 2). Much time was spent in walking in the ‘rice husks’ pens, but for some broilers, more sitting hour meant higher aggressive pecking behavior, which appeared more frequent in rice husks. Broilers increasingly performed many of their behaviors on the sand, but if only one type of litter was provided, they would perform those behaviors at a similar frequency on the sand or wood shavings (Song, 1996; Shields et al., 2004). Aggressive behavior means any purposive action of organism toward another with the actual or potential result of harming, limiting, or depriving it (Hurnik et al., 1995). So the aggressive behavior appeared higher in males.

Therefore, the welfare showed an improvement in the ‘sawdust’ pens because active behavior was more compared to the ‘rice husks’ pens.

Weight gain (WG) in stared during d10-25 was observed to be higher in rice husks than in sawdust (P<0.05, Table 4). WG during d26-40 and d56-70 appeared higher in sawdust than rice husks (P>0.05). WG in total tended to increase in sawdust higher than in rice husks (P<0.05). The effects of gender on weight gain (Table 4) appeared during d 10∼25 and the overall weight gain was higher in males than in females (P<0.05). According to Huang et al. (2009), at difference between rice husks and sawdust litter with the increased weight gain when using rice husks in the body weight gain differences. This was inconsistent with the results of our experiment. It is determined as a result of the difference in the characteristics between broilers and Korean Hanhyup broiler.