Litter composition and ammonia emission in aviary houses for laying hens: part III, water flow to the litter through fresh droppings

摘要

An observational study was carried out to investigate the level and variation of water input through fresh droppings to the litter in a tiered wire floor aviary housing system from 17 to 30 weeks of age of the hens. The mass balances of droppings(all excreta), manure on the belts and litter on the floor were modelled and these equations were used together with measurements of concentrations and newly developed measuring methods of flows and quantities of droppings, belt manure and litter. Fromthe differences in the concentration of ash, nitrogen, phosphorus and potassium between droppings, belt manure and litter, it was concluded that the transport of litter between the feathers of the hens to the belts was negligible. The relative amount ofexcreta deposited in the litter by the hens yielded a peak of ah out 50% around 22 weeks of age. Thereafter, the flow of droppings to the litter decreased to a stabilized level of about 10%. The flow of water to the litter through the droppings showed the same pattern, with a peak of about 45 g/d per hen and a stabilized level of about 7 g/d per hen. The actual peak might have been 10-30 g/d per hen higher, because measured water concentrations of the droppings were 40-90 g/kg lower than the waterconcentration of freshly excreted droppings. It was hypothesized that the peak in the water flow to the litter was caused by the changing behaviour of the hens, as indicated by the relative number of measured weights of the hens on scales in the litterarea and on a feeding tier. Hens spent less time in the litter area for scratching and dust bathing after 20 weeks of age, presumably because they spent more time in the nests for laying eggs and on the tiers for eating and drinking.