Litter lipid content affects dustbathing behavior in laying hens.

Within the European Union, the provision of dustbathing material in layer housing systems will be compulsory beginning in 2012. In cage systems, food particles are mainly used as litter material and are provided on scratching mats by an automatic transporting system. However, because dustbathing is a means for hens to remove stale lipids from their plumage, lipid content of a substrate may be an important asset with regard to its adequacy. This study analyzes dustbathing behavior as affected by lipid content of feed used as litter material. A total of 72 laying hens of 2 genotypes (Lohmann Selected Leghorn, Lohmann Brown) were kept in 12 compartments (6 hens each). Compartments were equipped with a plastic grid floor (G) and additionally contained 3 different dustbathing trays (each 1,000 cm(2)/hen) holding low-lipid (0.82%; L), normal-lipid (4.2%; N), and high-lipid (15.7%; H) food particles. The experiment began at 20 wk of life, and video recordings were done at wk 23, 26, and 29. Number of dustbaths, time spent dustbathing, average dustbath duration, foraging, and single behaviors within dustbaths were analyzed during the light period over 2 d in each observation week. Dustbaths occurred most frequently in the L compared with the N, H, and G treatments (all P < 0.001). Total time spent dustbathing was longest in the L treatment compared with the N and H treatments (P < 0.001). No difference in the average duration of single dustbaths was found between the L, N, and H treatments. However, when dustbath interruptions (less than 10 min) were excluded, the duration of single dustbaths was longer in the H compared with the L (P = 0.009) and N (P = 0.024) treatments. Foraging was most frequently observed in the N compared with the L, H, and G treatments (all P < 0.001). More body wing shakes occurred in the L compared with the N treatment, and the number of vertical wing shakes was higher in the N compared with the H treatment (all P ≤ 0.05). Our results showed that preference for a dustbathing substrate increased with decreasing lipid content, implying that food particles may not be a suitable dustbathing substrate.

Food, wood, or plastic as substrates for dustbathing and foraging in laying hens: A preference test.

The provision for dustbathing material will be a legal requirement in cage-housing systems for laying hens within the European Union beginning in 2012. At present, food particles are widely used and typically offered in small amounts on Astroturf mats one or more times per day to facilitate dustbathing, pecking, and scratching. In the present study, we compared layers' preference for food and 3 other (nonnutritive) substrates for foraging and dustbathing. In each of 2 identical trials, 72 hens of 2 genotypes (Lohmann Selected Leghorn and Lohmann Brown) were kept in 12 compartments (6 hens each). Compartments were equipped with a plastic grid floor and additionally contained 4 different dustbathing trays (each 1,000 cm(2)/hen) holding either wood shavings (WS), lignocellulose (LN, soft wood fiber, pelleted), Astroturf mat without substrate (AT), or food particles (FP). Hens were housed from 18 wk of age and video recordings were done at wk 21, 24, and 27. Time spent and frequency of dustbathing, duration of a single dustbath (DB), frequency of foraging behavior, and relative frequency and duration of behavioral patterns within a single DB were recorded during the light period over 2 d in each observation week. The FP treatment was preferred for foraging over WS, LN, and AT. Time spent dustbathing and number of DB were higher in LN compared with WS, FP, and AT, whereas average duration of a single DB was longer in FP compared with LN and WS. More vertical wing shakes and scratching bouts within a single DB were observed in LN compared with AT. Bill raking occurred more frequently in WS and LN in comparison to FP and AT. No differences in the relative durations of behavioral patterns within a single DB were found. In conclusion, FP were preferred for foraging but not for dustbathing, indicating that FP may not be an optimal dustbathing substrate for laying hens.