title: Incidence of non-laying in domestic hens.
abstract: 1. Egg production records of 31,455 individually caged hens, 27 to 34 weeks of age and of 4 genotypes, were examined. 2. Sixty-nine non-layers were identified in the 30 to 40 week age group, and examined post mortem; an incidence of 2.1 per 1000. 3. Some of the 69 individuals had more than one abnormality. Forty-two percent were internal layers, 34% had some form of neoplasia, 24% had an abnormal or diseased oviduct, 18% were sex reversals, 16% had a diseased ovary, 8% were of poor condition and considered culls, and 7% were in good condition, but with small, immature ovaries. 4. Of 54 birds not in lay at 27 weeks, 43 (80%) had come into lay by 34 weeks of age. 5. Genotype influenced the incidence of neoplasia and, in turn, the number of non-layers.
authors.affiliation: Department of Animal Husbandry, University of Bristol, England.
authors.forename: P D
authors.initials: PD
authors.lastname: Lewis
authors.forename: S E
authors.initials: SE
authors.lastname: Long
mesh_terms: D000818:Animals; D002645:Chickens; D005260:Female; D005838:Genotype; D006814:Hungary / Q000453:epidemiology; D015994:Incidence; D007247:Infertility, Female / Q000453:epidemiology / Q000209:etiology / Q000235:genetics / Q000662:veterinary*; D010051:Ovarian Neoplasms / Q000150:complications / Q000453:epidemiology / Q000662:veterinary; D010053:Ovary / Q000473:pathology; D010057:Oviducts / Q000473:pathology; D010058:Oviposition; D011201:Poultry Diseases / Q000453:epidemiology* / Q000209:etiology / Q000235:genetics