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A pin feather, sometimes called a "blood feather", is a developing feather on a bird.〔(Winged Wisdom Pet Bird Magazine - Weather The Feathers Molting in pet parrots and exotic birds - Birds, Birds, Birds )〕 This feather can grow as a new feather during the bird's infancy, or grow to replace one from moulting. The pin feather looks somewhat like a feather shaft. However, unlike a fully developed feather, the pin feather has a blood supply flowing through it. As such, if the pin feather is damaged, a bird can bleed heavily. As the pin feather grows longer, the blood supply is concentrated in only the base of the shaft, and the tip of the shaft encases the feather itself, in a waxy coating. As moulting birds preen, they remove the waxy coating, and the feather unfurls. When the blood has receded, the term "blood feather" is no longer synonymous with "pin feather" – it can only be referred to as a pin feather. ==Growth== Pin feathers begin to develop after the feather bud invaginates a cylinder of epidermal tissue around the base of the dermal papilla, forming the feather follicle. At the base of the feather follicle, epithelial cells proliferate to grow the epidermal collar or cylinder. As the epidermal cylinder extends through dermis, it differentiates into a protective peripheral sheath, longitudinal barb ridges, and growth plates. Over time these barb ridges lengthen helically, branch to create barbs and barbules, and fuse to form the rachis or central shaft. Moreover, the barb plate further differentiate into hooklets and cilia, while the marginal and axial plate die to form the intervening space within the feather structure. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Pin feather」の詳細全文を読む スポンサード リンク
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