Impact of light during laying hen egg incubation on hatch traits, growth and behaviour
Date
2019-06-27
Journal Title
Journal ISSN
Volume Title
Publisher
ORCID
0000-0002-0851-5987
Type
Thesis
Degree Level
Masters
Abstract
While the impact of various components of light have been studied in broilers and egg production hens, little is known about the impact that light wavelength and duration have on embryo development and welfare in the incubation phase. The overall objective of this research was to evaluate the effect of light wavelength and photoperiod during the incubation of fertile egg production hen eggs. In experiment 1, 640 Lohmann LSL (LSL) and 640 Lohmann Brown (LB) eggs were randomly distributed in 8 incubators. Two incubators per treatment were outfitted with red, blue, or white LED lights, and a 12L (Light):12D (Dark) photoperiod was used throughout incubation. The final two incubators remained dark. At hatch, 144 LSL and 144 LB pullets were placed in 3 brooding rooms under a Near Continuous (NC) or 3 rooms under an Intermittent (INT) lighting photoperiod. Post-hatch, pullet behaviour was video recorded on days 0, 2 and 4. The use of differing light wavelengths during incubation did not affect pullet behaviour post-hatch. A genotype effect was observed, as LSL pullets spent a greater percentage of time at the drinker on days 0 (P=0.012) and 2 (P=0.031), and at the feeder on days 2 (P<0.001) and 4 (P=0.005) compared to LB pullets. Brooding photoperiod also affected early behaviour, as pullets brooded under an INT photoperiod spent a greater percentage of time at the feeder on days 0 (P=0.036) and 2 (P=0.022), less percentage of time resting on days 0 (P=0.005), 2 (P<0.001) and 4 (P=0.004), and a higher percentage of time walking on days 2 (P=0.039) and 4 (P=0.041) than pullets under a NC photoperiod.
Experiment 2 was conducted with the objective of determining the effects of in-ovo photoperiod on hatch traits, growth and behaviour post-hatch. During incubation, 400 LSL eggs (n=3) were randomly distributed and exposed to one of 4 photoperiod treatments ((6L:18D (6L), 12L:12D (12L), 18L:6D (18L)) or 0L:24D (0L). At the hatch endpoint, males were evaluated for hatch traits (n=20/treatment), response to stress (heterophil to lymphocyte ratio (H/L), n=15 chicks/treatment) and composite asymmetry (sum of the difference between right and left; femur, tibiotarsus and metatarsus, n=20/treatment). Females (n=30/treatment) were evaluated for hatch traits at the hatch endpoint, and post-hatch growth to 21 days of age, early behavioural output, presence or absence of behaviour rhythms, H:L ratio, and composite asymmetry. Incubation time was reduced (P<0.05) with the use of light during incubation, with the greatest reduction occuring under 18L. However, the spread of hatch and hatchability were not affected. Stress tests (H/L ratio and composite asymmetry) of the male chicks were not affected by treatment. Body weight of female chicks at day 0 (P<0.001), 7 (P=0.001), 14 (P=0.017) and 21 (P=0.027) was higher for chicks hatched from 0L incubation, but flock uniformity did not differ. Stress indicators (composite asymmetry and H:L ratio) at day 21 did not differ. On hatch day the percentage of time chicks from 18L spent walking (P=0.029) was higher than chicks from 6L. Standing (P=0.015) was also higher in chicks from 18L compared to chicks from 0L and 12L incubation. Running (P=0.003) on hatch day was higher in chicks from 18L than chicks from 0L, 6L, and 18L incubation. Time spent at the feeder, drinker, preening, performing aggressive and low incidence behaviours at day 0 were not affected by in-ovo photoperiod. Behaviour rhythm was present in chicks post-hatch for the following behaviours: resting (P=0.035) and walking (P<0.001) during the photophase on day 0; walking on day 1 (P=0.023), resting (P=0.001), and foraging (P=0.017) on day 2, regardless of exposure to light during incubation. In conclusion, regardless of light wavelength used during incubation, provision of darkness such as in the INT brood photoperiod used in this study at an early age, increased chick activity compared to those reared under near-constant light. Overall light wavelength does not affect chick behaviour post-hatch, and the greatest impact with the use of lighting on chick behaviour is due to photoperiod length. A photoperiod up to 18L under red light can be used during incubation without negative effects on stress measures and chick’s behaviour, but it might reduce chick weight at hatch.
Description
Keywords
In-ovo lighting, behaviour
Citation
Degree
Master of Science (M.Sc.)
Department
Animal and Poultry Science
Program
Animal Science