Feed Intake of Laying Hens

SummaryA number of equations have been reported for the prediction of daily metabolizable energy (ME) intake of the laying hen. Predictions using 13 equations have been compared with observed ME intake in 16 locations ranging from Norway to Australia. ME intake predicted by all equations was similarly correlated with observed feed intake—ranging from 0.82 to 0.90, with standard errors of 5.7 to 7.4 kcal/day. However, some equations consistently underestimated ME intake, estimating as little as 78% of the observed ME intake.A number of factors are identified as influencing the accuracy of the prediction equations; these include seasonal effects, temperature, air velocity, housing systems, number of birds per cage and genotype. Feed restriction during the laying phase, but not during growth also affects the accuracy of the prediction.An equation is derived connecting air velocity and temperature to increased ME consumption, and a table of corrections presented for a range of temperatures and wind speeds.