Effects of AM/PM feeding on behaviour, range use and welfare indicators of free-range laying hens

Context AM/PM feeding (also known as ‘split-feeding’) is designed to meet a hens’ nutrient requirement via two diets, namely, high protein and energy in the morning/early afternoon (AM) and high calcium during the mid-afternoon/evening (PM), compared with a single conventional diet over 24 h. Aims The study aimed to investigate the effects of AM/PM feeding on free-range laying hens, focusing on welfare, behaviour and health. It was hypothesised that AM/PM feeding, aligned with the hen’s diurnal physiology, would improve behaviour, welfare, and health compared with a conventional diet. Methods The study was conducted at a free-range research facility by using two dietary treatments, namely, conventional layer hen diet (Control) and the AM/PM diet. Diets were fed to nine replicate pens of 20 hens each, giving a total of 360 Hy-Line Brown laying hens (18 pens) when they were between 34 and 53 weeks of age (WOA). The AM diet (2980 kcal/kg apparent metabolisable energy corrected for nitrogen (AMEn), 20.1% crude protein (CP), 2.5% calcium (Ca) was provided from 08:00 hours to 16:00 hours, and the PM diet (2580 kcal/kg AMEn, 17.5% CP, 5.6% Ca) from 16:00 hours to 08:00 hours. In contrast, the conventional diet (2780 kcal/kg AMEn, 18.8% CP, 4.1% Ca) was provided continuously. Hen behaviour was recorded using overhead cameras between 49 and 50 WOA and assessed via behavioural ethogram. Individual hen ranging behaviour was monitored using radio-frequency identification (RFID) from 39 to 48 WOA. Hen fearfulness was evaluated through tonic immobility and novel object test during 51–52 WOA. At 53 WOA, hens were assessed for health, tibia bone quality, and faecal glucocorticoid metabolites. Key results AM/PM feeding reduced feather pecking (P = 0.01) and increased outdoor range use (2.85 vs 2.47 h/day; P < 0.001). It also showed an effect approaching statistical significance for faster exploration of novel objects (P = 0.08). AM/PM feeding improved tibia ash content (P = 0.03) and breaking strength (P = 0.04). Conclusions AM/PM feeding demonstrated potential benefits for laying hen welfare, including reduced feather pecking, increased outdoor activity, and improved bone health, compared with the conventional diet. Implications AM/PM feeding may enhance the health and welfare of free-range laying hens, although further long-term studies are needed to confirm its potential.