棲架高度與棲木粗細對於台灣土雞育成期行為及生長性狀之影響

Abstract

本研究欲探討棲架高度及粗細對於台灣土雞育成期行為及生長性狀之影響，希冀推薦適當棲架設計給予商業土雞場。試驗使用之台灣土雞為國立中興大學育成L2品系，採公母分飼，於5至16週齡進行試驗。試驗一使用公母雞共528隻，比較三種不同高度之雙層棲架(H30、H50及H70組，低層棲架高度分別為30, 50與70 cm)；試驗二公母雞共672隻，比較三種不同粗細之雙層棲架(D1.9、D3.2及D3.8組，棲架直徑分別為1.9, 3.2與3.8 cm)。

兩個試驗一致的重要結果為：公雞鬥爭頻率較高，無論日間和夜間都較會利用棲架。而母雞就表現較多的覓食和整羽行為。雞隻利用棲架早晚多，中午少。公雞利用棲架的頻率隨週齡而增加，母雞反而下降。且公雞利用棲架次數與體重呈負相關，母雞相關性則不顯著。

試驗一結果發現，公雞中，日間、夜間利用棲架頻率均以H70組最少；H30組利用棲架頻率最高，使H30組公雞鬥爭行為最少，羽毛外觀較佳；且H30組公雞體重顯著較重、冠面積顯著較大，Tonic Immobility時間在H30組公雞亦有趨勢較短，顯示社會壓力較小。缺點在於H30組公雞背部羽毛有較多糞便污染情形，且16週齡H30組公雞龍骨外觀較差但不顯著。整體來說，對於育成期的台灣土雞，30 cm可能是較適合的高度，但仍有羽毛、龍骨外觀之缺點仍待克服。

試驗二結果發現棲架粗細對育成期日間與夜間利用棲架的頻率均無顯著影響，對於體重、冠面積、腳爪外觀及Tonic Immobility時間也均無顯著影響。但14週齡後，公雞D1.9組上層棲架使用頻率降低，而下層棲架利用頻率增多，顯示高層棲架過細時，易造成較大雞隻使用頻率減低；也可能因上層使用頻率較少，使D1.9組16週齡羽毛污染較少。 故在台灣土雞的棲架設計，建議公雞使用棲架最底層高度為30cm，粗細直徑為3.2cm。母雞在公母分飼條件下，較少使用棲架，可考慮不裝設棲架。

The purpose of this study was to realize the effect of perch height and diameter on the behaviours and production efficiency of Taiwan Country chicken during rearing period. The information may be useful to design appropriate perches to commercial farms of Taiwan Country chicken. The Taiwan Country Chicken studied were L2 strain bred by the National Chung Hsing University. Males and females were separately reared and studied from 5 to 16 weeks of age. Experiment 1 used 528 chickens to compare two-stair perches with three different height (the heights of the lower perch in H30, H50, and H70 groups were 30, 50 and 70 cm). Experiment 2 used 672 chickens to compare three different diameters of perches (the diameters of perches in D1.9, D3.2, and D3.8 groups were 1.9, 3.2 and 3.8 cm). The following results were consistent for both experiments. Males had higher frequency of agonistic behavior, and perched more often during both daytime and night time. Females displayed more foraging and preening behaviors. Chickens perched more often in the morning and late afternoon than in the middle of the day. Perching increased with age in males but decreased in females. Results of Experiment 1 indicated that in males, H70 perched less often than the other groups during both daytime and night time; H30 utilized perches more often and had less frequency of agonistic behavior and better feather condition; in additions, H30 males had significantly heavier body weight and larger comb area, and a tendency to have shorter TI time which suggests that they were under less social stress. The problems of H30 males were feather contaminated with feces and slightly worse keel score at 16 weeks of age. In general, 30 cm may be the appropriate height for Taiwan Country chicken during the rearing period. However, the feather and keel problems need further studies. Results of Experiment 2 indicated that size of perch diameter did not significantly affect the frequency of perching during neither daytime nor night time. It did not have any significant effect on body weight, comb size, claw deformation or TI duration time. However, D1.9 males decreased the use of upper-perch and increased the use of lower-perch after 14 weeks of age. It suggested that too small the size of the perch may make the large bird unwilling to use them. It was also possible that the less upper-perch perching frequency made D1.9 males had less feces contamination on feather at 16 weeks of age. Therefore, for the design of perch for Taiwan Country chicken, the males may use a perch, with the lowest level 30 cm height from the ground, and a diameter of 3.2 cm. Females reared separately from males may not need any perches.