egg tooth

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egg tooth

n.
A hard toothlike projection on the beak of an embryonic bird or the snout of an embryonic reptile that is used to break through the eggshell upon hatching and that later falls off or is absorbed.

egg tooth

a small horny projection at the tip of the bill in birds used to pierce the egg shell.

egg

1. an ovum; a female gamete.
2. an oocyte.
3. a female reproductive cell at any stage before fertilization and its derivatives after fertilization and even after some development.
4. hen egg, consisting of a blastodisk, remnant of the nucleus in a mass of white yolk sitting on top of the yellow yolk, the yolk suspended by two twisted strands of mucin-like protein, the chalazae, from the two poles of the egg, two yolk membranes that separate the yolk from the albumen, the albumen or white of the egg, which is in four separate layers of liquid and jelly material, two thin shell membranes and an eggshell. See also avian oogenesis.
5. helminth egg.

egg bound
a disease of cage birds, birds in zoological collections and in fish. In birds the hen may show pain and be straining and the egg may be palpable. The syndrome is comparable with dystocia in a viviparous animal. In fish the only sign is the wrinkled, shriveled eggs.
egg count
counting of helminth eggs as an estimate of the parasite status in the animal or group. Flotation techniques and special counting chambers are used. The results are expressed as eggs per gram (e.p.g) of feces.
egg dipping
dipping of hatchery eggs in antibiotic solutions, especially erythromycin or tylosin, to prevent the transmission of infections from adults to chickens.
egg drop syndrome
first observed in 1976 the disease is caused by an adenovirus and characterized by the hens laying a reduced number of thin-shelled or shell-less eggs. Subsequently the egg yield is reduced.
egg eating
a vice which begins without apparent reason. A high rate of egg breaking in the unit encourages birds to begin. Many techniques are used in prevention but frequent egg removal is essential.
grader egg
a reject from those destined for household use; used in petfood manufacture.
egg heating
heating eggs in a hot-air incubator for 12-14 hours to reduce the transmission of infection on the egg exterior.
egg peritonitis
see egg peritonitis.
egg retention
see egg bound (above).
egg shell
secreted around the egg mass and membranes during its last 15 hours in the uterus; composed of calcium carbonate and a glycoprotein matrix; surrounded by the cuticle.
thin-shelled egg
occurs in egg drop syndrome (see above), DDT poisoning. The shell of the egg is very thin, often missing altogether.
egg tooth
the additional tip to the beak in birds that is used by the hatching chick to peck out the circular hatch of shell to allow it to emerge. The egg tooth drops off in a few days. Called also bean.
egg transmission
transmission of disease from hen to chicken and between chickens via infection in the egg, e.g. Mycoplasma gallisepticum, M. meleagridis.
egg white injury
the effects of biotin deficiency induced by feeding of raw egg whites (albumen). The factor responsible is avidin which binds biotin, preventing absorption.
egg yield
in domestic fowl the normal annual average over a large, national population is about 130 eggs per bird; good units average 200.