Feather in the context of "Bird"

A nutrient is a substance used by an organism to survive, grow and reproduce. The requirement for dietary nutrient intake applies to animals, plants, fungi and protists. Nutrients can be incorporated into cells for metabolic purposes or excreted by cells to create non-cellular structures such as hair, scales, feathers, or exoskeletons. Some nutrients can be metabolically converted into smaller molecules in the process of releasing energy such as for carbohydrates, lipids, proteins and fermentation products (ethanol or vinegar) leading to end-products of water and carbon dioxide. All organisms require water. Essential nutrients for animals are the energy sources, some of the amino acids that are combined to create proteins, a subset of fatty acids, vitamins and certain minerals. Plants require more diverse minerals absorbed through roots, plus carbon dioxide and oxygen absorbed through leaves. Fungi live on dead or living organic matter and meet nutrient needs from their host.

Different types of organisms have different essential nutrients. Ascorbic acid (vitamin C) is essential to humans and some animal species but most other animals and many plants are able to synthesize it. Nutrients may be organic or inorganic: organic compounds include most compounds containing carbon, while all other chemicals are inorganic. Inorganic nutrients include nutrients such as iron, selenium, and zinc, while organic nutrients include, protein, fats, sugars and vitamins.

Pinnation (also called pennation) is the arrangement of feather-like or multi-divided features arising from both sides of a common axis. Pinnation occurs in biological morphology, in crystals, such as some forms of ice or metal crystals, and in patterns of erosion or stream beds.

The term derives from the Latin word pinna meaning "feather", "wing", or "fin". A similar concept is "pectination", which is a comb-like arrangement of parts (arising from one side of an axis only). Pinnation is commonly referred to in contrast to "palmation", in which the parts or structures radiate out from a common point. The terms "pinnation" and "pennation" are cognate, and although they are sometimes used distinctly, there is no consistent difference in the meaning or usage of the two words.

Theropoda (/θɪəˈrɒpədə/; from ancient Greek θηρίο- ποδός [θηρίον, (therion) "wild beast"; πούς, ποδός (pous, podos) "foot"]) is one of the three major clades of dinosaur, alongside Ornithischia and Sauropodomorpha. Theropods, both extant and extinct, are characterized by hollow bones and three toes and claws on each limb. They are generally classed as a group of saurischian dinosaurs, placing them closer to sauropodomorphs than to ornithischians. They were ancestrally carnivorous, although a number of theropod groups evolved to become herbivores and omnivores. Members of the subgroup Coelurosauria were most likely all covered with feathers, and it is possible that they were also present in other theropods. In the Jurassic, birds evolved from small specialized coelurosaurian theropods, and are currently represented by about 11,000 living species, making theropods the only group of dinosaurs alive today.

Theropods first appeared during the Carnian age of the Late Triassic period 231.4 million years ago (Ma) and included the majority of large terrestrial carnivores from the Early Jurassic until the end of the Cretaceous, about 66 Ma, including the largest terrestrial carnivorous animals ever, such as Tyrannosaurus and Giganotosaurus, though non-avian theropods exhibited considerable size diversity, with some non-avian theropods like scansoriopterygids being no bigger than small birds.

A bristle is a stiff hair or feather (natural or artificial), either on an animal, such as a pig, a plant, or on a tool such as a brush or broom.

Poultry (/ˈpoʊltri/) are domesticated birds kept by humans for the purpose of harvesting animal products such as meat, eggs or feathers. The practice of raising poultry is known as poultry farming. These birds are most typically members of the superorder Galloanserae (fowl), especially the order Galliformes (which includes chickens, quails, and turkeys). The term also includes waterfowls of the family Anatidae (ducks and geese) but does not include wild birds hunted for food known as game or quarry.

Recent genomic studies involving the four extant junglefowl species reveals that the domestication of chicken, the most populous poultry species, occurred around 8,000 years ago in Southeast Asia. This was previously believed to have occurred around 5,400 years ago, also in Southeast Asia. The process may have originally occurred as a result of people hatching and rearing young birds from eggs collected from the wild, but later involved keeping the birds permanently in captivity. Domesticated chickens may have been used for cockfighting at first and quail kept for their songs, but people soon realised the advantages of having a captive-bred source of food. Selective breeding for fast growth, egg-laying ability, conformation, plumage and docility took place over the centuries, and modern breeds often look very different from their wild ancestors. Although some birds are still kept in small flocks in extensive systems, most birds available in the market today are reared in intensive commercial enterprises.

Plumage (from Latin pluma 'feather') is a layer of feathers that covers a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies and may vary with sex and age classes. Within a few species, there can be different colour morphs. The placement of feathers on a bird is not haphazard but rather emerges in organised, overlapping rows and groups, and these feather tracts are known by standard names.

Most birds moult twice a year, resulting in a breeding plumage and a non-breeding plumage; one of the moults, usually the one just after breeding, is a complete moult replacing all the feathers; the other, usually the one just before breeding, is often only a partial moult, with new small body feathers but not replacing the larger flight feathers in the wings and tail. Some very large birds, like eagles, replace their flight feathers slowly but continuously throughout the year, to minimise loss of flight efficiency. Many ducks and some other species such as the red junglefowl have males wearing a bright plumage while breeding and a drab eclipse plumage for some months afterward. Many passerine species have only one moult per year, with changes in plumage resulting from the wear of differently-coloured feather tips. Young birds have a juvenile plumage, which is replaced in the months after fledging by the first-winter plumage; in long-lived birds with slow maturation like gulls, this is followed by a succession of second, third, and sometimes fourth year immature plumages.