23. The laying cage is basically a perforated box with a sloping floor and ancillary equipment for feeding and drinking, with egg collection arrangements mounted on the front. In recent years there have been several detailed changes to cage design and construction to improve access for depopulation, production efficiency and enhance bird welfare. Mortality rates in caged birds are generally now very low.
24. Large, modern units are usually highly mechanised with computerised controls for the environment, feeding, manure removal and egg collection. Blocks of cages can be as much as eight tiers high, although four to six tiers are common in this country. Most cages manufactured during the past ten years provide hens with 500cm²/bird in five bird colonies.
25. Some manufacturers offer the option of a perch and/or an abrasive claw shortener on the baffle plate of their cages. Studies on enrichment of cages by the additional provision of nest sites and dust baths have given encouraging results on a small experimental scale. Larger scale experiments are underway at ADAS Gleadthorpe Poultry Research Centre and other research institutes in Europe.