Ebook Farm animal behaviour (2/E): Part 2

Part 2 book "Farm animal behaviour" includes content: Domestic fowl (Gallus gallus domesticus), turkey (Meleagris gallopavo), goose (Anser anser f. domesticus, anser cygnoides f. domesticus), domestic duck (Anas platyrhynchos) and muscovy duck (Cairina moschata), deer - fallow deer (dama dama) and red deer (cervus elaphus), ratite - ostrich (struthio camelus), rhea or nandu (rhea americana) and emu (dromaius novaehollandiae).
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Ebook Farm animal behaviour (2/E): Part 2 PART II Domesticated Birds 297 7 Domestic Fowl (Gallus gallus domesticus) 7.1 Domestication, Changes in the Animals, their Environment and Management The ancestor of the domestic fowl is the Red Jungle Fowl (Gallus gallus) (Fig. 7.1). Modern forms of these jungle fowl are still found today in South-east Asia, and the domesticated bird can be regarded as a subspecies (G. gallus domesticus). Estimates vary but domestication is thought to have occurred about 8000 years ago, first in India and China, then spreading along trade routes. Fig. 7.1. Jungle hen and cock. (Image courtesy of P. Jensen.) However, recent studies of the chicken genome have found that at least one other wild ancestor (the grey jungle fowl, Gallus sonneratii) was involved in development of the domestic fowl (Fig. 7.2) in addition to the Red Jungle Fowl (Eriksson et al., 2008). Genetic studies have been able to demonstrate that domestication occurred about 8000 years ago (Rubin et al., 2010), but still the early history of domestication is a matter of controversy (Peters et al., 2016). This is partly in agreement with the archeological findings that have been reported. 298 Fig. 7.2. Domestic hens with a cock. (Image courtesy of photo archive HMH Department.) Some scientists proposed that the domestication of chickens took place in the Indus valley around 2500–2100 bc. However, others claimed that the domestication of chickens might have taken place as early as 6000 bc. On the other hand, others suggested that chickens were neither widely kept nor distributed in central and northern China during the early and middle Holocene period. Again, others suggested that domestication might have taken place in South-east Asia, and birds were taken to China by humans. Thailand and its neighbouring regions were the cradle of domestic chickens. Some claim that there is evidence implicating multiple maternal origins of chicken centred around South and South-east Asia. Chickens were taken from South-east Asia by humans and became well established at Neolithic sites in northern China and, later, in India at about 2000 bc. Japanese chickens were thought to have been introduced via similar South-east Asian regions. All these results indicate that our current knowledge of chicken domestication and genetic diversity remains far from complete (West and Zhou, 1989; Crawford, 1990, 1992; Akishinonomiya et al., 1994, 1996; Komiyama et al., 2004; Liu et al., 2006; Shahbazi et al., 2007; Dessie et al., 2012; Eda et al., 2016). Many routes have been proposed to explain the distribution of domestic chickens to Europe. A review indicated that chickens were introduced to Iran from the Indus valley around 2500–2000 bc, from where they spread to Europe. Another proposal is that chickens were taken from Iran to Greece and Italy across the Aegean Sea or directly to central Europe through Scythia and southern Russia. Other possible routes include dispersion through Iran to the Mediterranean, and through China and Russia to Europe. Some scientists suggest that north European chickens were introduced from China through Russia, and not from the Indus Valley. Chickens in the Mediterranean were morphologically different from those found in northern Europe. Mediterranean chickens could have been introduced through Iran (West and Zhou, 1989; Crawford, 1992; Shahbazi et al., 2007; Dessie et al., 2012). 299 The purpose of domestication has probably been changing over time. Initially, birds were likely used for sacrifice for ceremonial purposes, because of their beautiful plumage, and for cockfighting. Although there existed wood-heated incubators in old Egypt, it was not until the Roman times that the bird’s potential as an agricultural animal was developed, and laying breeds selected for high egg production, and even a poultry industry, were established. This industry collapsed when the Roman Empire collapsed, and the large-scale selection of birds for commercial use did not resume again until the 19th century (Wood-Gush, 1971; West and Zhou, 1989; Crawford, 1990; Siegel et al., 1992). The species hen is promiscuous, with males mating with several females. The male may defend his harem of females from other males. Jungle fowl are omnivores, spending a large portion of their day pecking and scratching in the ground for seeds, worms and insects. Studies of the way in which semi-wild, free-ranging jungle fowl in zoos allocated their time between different activities showed that in 60% of all minutes during the active part of the day, hens were seen to be ground pecking and in 34% they were ground scratching (Dawkins, 1989). Domestic hens also spend a large proportion of their day pecking and scratching. The beak is the main exploratory organ of the bird. It is well innervated at its tip, with collections of touch receptors that allow the birds to peck accurately (Desserich et al., 1983). Several characteristics predisposed jungle fowl to domestication. They are social and gregarious, living in groups of 1–2 males and 2–5 females plus young, which has allowed them to be managed in groups. They have a hierarchical structure, probably based on individual recognition, which reduces the risk of injury caused by fighting. They show promiscuous sexual behaviour, which allows any male to be mated with any female and so facilitates artificial selection. Fowl have flexible dietary requirements and are adaptable to a wide range of environments. All these traits have been used to advantage in commercial poultry production. Domesticated hens have retained the jungle fowl’s strong motivation to perform nesting, perching and dust bathing behaviour (Keeling, 2002). The domestic fowl (G. gallus domesti ...