Assessment of lighting needs by W-36 laying hens via preference test

Abstract

Light intensity, spectrum and pattern may affect laying hen behaviors and production performance. However, requirements of these lighting parameters from the hens' standpoint are not fully understood. This study was conducted to investigate hens' needs for light intensity and circadian rhythm using a light tunnel with five identical compartments each at a different fluorescent light intensity of <1, 5, 15, 30 or 100 lux. The hens were able to move freely among the respective compartments. A group of four W-36 laying hens (23 to 30 weeks of age) were tested each time, and six groups or replicates were conducted. Behaviors of the hens were continuously recorded, yielding data on daily time spent, daily feed intake, daily feeding time, and eggs laid under each light intensity and daily inter-compartment movement. The results show that the hens generally spent more time in lower light intensities. Specifically, the hens spent 6.4 h (45.4%) at 5 lux, 3.0 h (22.1%) at 15 lux, 3.1 h (22.2%) at 30 lux and 1.5 h (10.3%) at 100 lux under light condition; and an accumulation of 10.0 h in darkness (<1 lux) per day. The 10-h dark period was distributed intermittently throughout the day, averaging 25.0 ± 0.4 min per hour. This hourly light-dark rhythm differs from the typical commercial practice of providing continuous dark period for certain part of the day (e.g. 8 h at night). Distributions of daily feed intake (87.3 g/hen) among the different light conditions mirrored the trend of time spent in the respective light intensity, that is, highest at 5 lux (28.4 g/hen, 32.5% daily total) and lowest at 100 lux (5.8 g/hen, 6.7%). Hen-day egg production rate was 96.0%. Most of the eggs were laid in <1 lux (61.9% of total) which was significantly higher than under other light intensities ( P < 0.05). Findings from this study offer insights into preference of fluorescent light intensity by the laying hens. Further studies to assess or verify welfare and performance responses of the hens to the preferred lighting conditions and rhythm over extended periods are recommended.

Choice Between Fluorescent and Poultry-Specific LED Lights by Pullets and Laying Hens

“…Likewise, L1F2 (33.6% ±1.2%) and L2F1 (31.6% ±1.4%) for L FL were significantly higher than L0F3 (20.6% ±1.7%, p = 0.005 and p <0.001, respectively) or L3F0 (14.2% ±1.2%, p < 0.001 and p < 0.001, respectively). These distribution patterns differed from those found in a previous study in which laying hens spent about 60% of the time during the light period with three or four hens in the same cage when four hens were housed in five interconnected cages (Ma et al, 2016).…”

“…ISA Brown hens were observed to eat for the longest time under the brightest light intensity (200 lux) and for the shortest time under the dimmest light intensity (<1 lux) when given free choice of light intensities of <1, 6, 20, or 200 lux (Prescott and Wathes, 2002). In contrast, Hy-Line W-36 commercial layers were found to have the highest feed intake at 5 lux (32.5%) and the lowest feed intake at 100 lux (6.7%) when given free choice of light intensities of <1, 5, 15, 30, or 100 lux (Ma et al, 2016).…”

“…The purpose of the acclimation chamber was to train the birds to use the passageway and expose them to the lights under study. Detailed specifications of the test tunnel and the acclimation chamber, including their construction, ventilation system (air duct, inlet and exhaust fans), and egg and manure collection systems, were given in a previous article (Ma et al, 2016).…”

“…Preference tests investigate the instantaneous behavioral responses of animals to various environmental stimuli, rather than the long-term physiological impacts; thus, they can offer an efficient assessment of animal preferences (Ma et al, 2016). As a result, preference tests have been used extensively in poultry studies to assess different environmental conditions, including floor type (Hughes, 1976), nest box (Appleby et al, 1984;Millam, 1987), perch height and shape (Struelens et al, 2008;Lambe and Scott, 1998), ammonia level (Green, 2008;Kashiha et al, 2014), and various light regimens, as cited below.…”

Layer pullet preferences for light colors of light-emitting diodes

“…The assignment of four light colors followed another 4×4 Latin Square design (Table 1) in each test period, so each compartment contained all four light colors during the four periods. This was to prevent any compartment preferences to affect the choices of poultry (Ma et al ., 2016). Temperature and relative humidity were maintained at 23.1±0.5°C and 20±1% during the experiment period.…”