R. A. Blatchford

The effect of light intensity on the behavior, eye and leg health, and immune function of broiler chickens

Broilers are typically raised commercially in dim lighting. It has been suggested that providing brighter light intensity could improve health and provide opportunities for more normal behavioral rhythms. We examined the effects of 3 photophase light intensities (5, 50, and 200 lx) on activity patterns, immune function, and eye and leg condition of broilers (n = 753; 6 replicate pens/treatment). Broilers were reared with one of these intensities from 1 to 6 wk of age; photoperiod consisted of 16L:8D with 1 lx intensity during the scotophase. Broilers reared with 5 lx were less active (P = 0.023) during the day than 50 or 200 lx and showed less (P < 0.0001) change in activity between day and night than 50 or 200 lx. There was no difference between treatments for final BW (2.30 +/- 0.02 kg) or for most immune parameters (IgG primary and secondary responses to keyhole limpet hemocyanin, B and T lymphocyte proliferation, plasma lysozyme, haptoglobin, NO, whole blood killing of Escherichia coli and Staphylococcus aureus), but there was a trend (P = 0.072) for a greater IgM response in 50 lx (6.21 titer) than 5 lx (5.78 titer), with 200 lx (5.92 titer) intermediate. There was no effect of light intensity on back-to-front (1.13 +/- 0.01 cm) or side-to-side (1.48 +/- 0.01 cm) diameter of the eyes or on corneal radii (0.82 +/- 0.01 cm), but 5 lx (2.33 +/- 0.07 g) had heavier eyes (P = 0.002) than 50 lx (2.09 +/- 0.04 g) or 200 lx (2.11 +/- 0.04 g). There were no differences in gait score, although 200 lx broilers had more hock and footpad bruising (P = 0.038) but fewer erosions (P = 0.006) than 5 or 50 lx. Increased daylight intensity had little effect on broiler health but resulted in more pronounced behavioral rhythms.

Determination of space use by laying hens using kinematic analysis

Two states in the United States now have legislation requiring that laying hens be provided with sufficient space to perform particular behaviors. To provide a framework for translating these performance standards into a space requirement, kinematic analysis was used to measure the amount of space needed for White Leghorn hens to stand, turn around 180°, lie down, and wing flap. Hyline W-36 hens (n = 9) were marked on the tops of their heads and the tips of both wings and 3 toes with black livestock marker. Each hen was then placed in a floor pen (91.4 × 91.4 cm) and filmed using 2 high-speed cameras. The resulting images were processed using a software program that generated 3-dimensional space use for each behavior. Because none of the hens lay down in the test pen, the 2-dimensional space required for lying was determined by superimposing a grid over videos of the hens lying down in their home cages. On average, hens required a mean area of 563 (± 8) cm(2) to stand, 1,316 (± 23) cm(2) to turn around, 318 (± 6) cm(2) to lie down, and 1,693 (± 136) cm(2) to wing flap. The mean heights used were 34.8 (± 1.3) cm for standing, 38.6 (± 2.3) cm for turning, and 49.5 (± 1.8) cm for wing flapping. However, space requirements for hens housed in multiple-hen groups in cage or noncage systems cannot be based simply on information about the space required for local movement by a single hen. It must also incorporate consideration of the tendency of hens in a flock to synchronize their behaviors. In addition, it must include not just local movement space but also the space that hens may need to use for longer-distance movements to access resources such as food, water, perches, and nest boxes.

Contrast in light intensity, rather than day length, influences the behavior and health of broiler chickens.

Day length and intensity are commonly manipulated aspects of the light environment in commercial broiler production. Both influence circadian rhythms, but it is unclear if they do this independently or synergistically. The effect of light:dark (20L:4D, 16L:8D) and intensity contrasts (1 lx:0.5 lx, 200 lx:0.5 lx) on broiler behavior and health (n=1,004, 4 replicates/treatment) was evaluated. Activity was measured using passive infrared detection, and feeding activity was measured by the amount of feed consumed/h over one 24-h period each week. Broilers were gait scored and weighed at 6 wk of age. Following euthanasia, eyes were dissected from 30 birds/treatment. Behavior and performance were analyzed using the GLM, gait score using the Kruskal-Wallis test, and eye measures using a MANOVA. The 200 lx birds were more active (P=0.03) and fed more (P=0.001) during the photophase but were less active (P=0.02) and fed less (P<0.001) during the scotophase, than the 1 lx birds. There were no differences in G:F (mean±SEM, 1.63±0.01 kg of feed/kg of BW). However, 1 lx birds were slightly heavier (2.79±0.01 kg; P=0.02) than 200 lx birds (2.72±0.01 kg). The 200 lx birds had better (P<0.001) mean gait scores than 1 lx birds, although treatment differences were small. One lux birds had greater side-to-side (18.86±0.11 mm vs. 17.63±0.11 mm, P<0.001) and back-to-front (13.39±0.09 mm vs. 12.89±0.09 mm, P<0.001) eye diameters and heavier eyes (2.42±0.03 g vs. 1.99±0.03 g, P<0.001) than 200 lx birds. There was only one effect of light:dark, with 16:8 having greater back-to-front eye diameters than 20:4 (13.30±0.10 mm vs. 13.00±0.10 mm, P=0.02). There were no interactions. These results indicated that light intensity, not day length, was the major factor affecting broiler behavior and health under these lighting conditions. Low contrast light intensity dampened behavioral rhythms and had possible health effects.

The utilization of the Welfare Quality® assessment for determining laying hen condition across three housing systems

The Welfare Quality(®) Assessment protocol for poultry ( WQA: ) provides animal-based measures allowing welfare comparisons across farms and housing systems. It was used to compare Lohmann LSL Classic White hens housed in an enriched colony ( EC: ), aviary ( AV: ), and conventional cage system ( CC: ) on a commercial farm over 2 flock cycles. Hens (n = 100/system) were scored on a variety of measures. A baseline measurement was made at placement at 19 wk of age for 1 flock, since AV hens had been reared in an aviary pullet facility ( AVP: while EC and CC hens were reared in a conventional pullet facility ( CCP: ). Hens in all systems were then assessed at 52 and 72 wk of age. Necropsies were performed on all mortalities 1 wk before and after the WQA sampling. WQAs were analyzed using Mann-Whitney U and Kruskal-Wallis tests for prevalence and Fishers exact tests for severity. There was an effect of rearing, with AVP having shorter claws (P = 0.01), dirtier feathers (P = 0.03), and more keel abnormalities (P < 0.0001) than CCP at placement. For the hens, there were several significant housing system effects across flocks and age periods (all P ≤ 0.05). AV and EC hens had more keel abnormalities than CC hens. They also had fewer foot abnormalities than CC hens, although those in AV hens were more severe. AV hens had consistently dirtier feathers than EC and CC hens. While AV hens had the best overall feather cover, feather loss patterns suggested that loss was due to head pecking for AV, whereas in EC and CC it was due to cage abrasion. The necropsy findings and the WQA results were similar, except that the WQA failed to find enteritis at 19 wk, although it was detected in the necropsies during this sampling period. These results show that the WQA is a useful tool for detecting hen condition differences across housing systems.

Microbiological impact of three commercial laying hen housing systems

Hen housing for commercial egg production continues to be a societal and regulatory concern. Controlled studies have examined various aspects of egg safety, but a comprehensive assessment of commercial hen housing systems in the US has not been conducted. The current study is part of a holistic, multidisciplinary comparison of the diverse aspects of commercial conventional cage, enriched colony cage, and cage-free aviary housing systems and focuses on environmental and egg microbiology. Environmental swabs and eggshell pools were collected from all housing systems during 4 production periods. Total aerobes and coliforms were enumerated, and the prevalence of Salmonella and Campylobacter spp. was determined. Environmental aerobic and coliform counts were highest for aviary drag swabs (7.5 and 4.0 log cfu/mL, respectively) and enriched colony cage scratch pad swabs (6.8 and 3.8 log cfu/mL, respectively). Aviary floor and system wire shell pools had the greatest levels of aerobic contamination for all eggshell pools (4.9 and 4.1 log cfu/mL, respectively). Hens from all housing systems were shedding Salmonella spp. (89–100% of manure belt scraper blade swabs). The dry belt litter removal processes for all housing systems appear to affect Campylobacter spp. detection (0–41% of manure belt scraper blade swabs) considering detection of Campylobacter spp. was much higher for other environmental samples. Aviary forage area drag swabs were 100% contaminated with Campylobacter spp., whereas enriched colony cage scratch pads had a 93% positive rate. There were no differences in pathogen detection in the shell pools from the 3 housing systems. Results indicate egg safety is enhanced when hens in alternative housing systems use nest boxes. Additionally, current outcomes indicate the use of scratch pads in hen housing systems needs to be more thoroughly investigated for effects on hen health and egg safety.

Light intensity during rearing affects the behavioural synchrony and resting patterns of broiler chickens

1. The effect of light intensity on behavioural synchrony and rest in broilers was investigated by randomly assigning 504 Cobb chicks to environmental chambers at low (5 lux), moderate (50 lux), or high (200 lux) daytime illumination under a 16 h L : 8 h D light cycle. We hypothesised that behavioural synchrony and resting behaviour would be affected by light : dark amplitude, and predicted that broilers reared at higher intensities would show increased synchrony and thus have fewer, but longer, resting bouts during the scotophase, since these bouts would be less likely to be interrupted by active birds. 2. Digital recordings were made for 48 h from weeks 3 to 5 of age, and scan samples taken of 11 behaviours at 15-min intervals. Z-scores for the amount of synchronisation were calculated using the kappa coefficient of agreement. Frequency and length of resting bouts and the number of resting bout interruptions by flockmates were also calculated from continuous observations of 4 focal broilers per pen. 3. Resting and sitting behaviour were significantly synchronised or showed a strong trend towards synchronisation in all treatments during the 3 weeks of observation. There were significant treatment differences in the degree of synchrony for preen, eat, rest and forage, with broilers reared in 200 lux showing the greatest degree of synchrony. 4. During the scotophase, broilers reared with high illumination had fewer, longer, and less interrupted bouts of resting than those reared with moderate or low illumination. During the photophase, broilers in the low-illumination treatment had more frequent, longer, and more interrupted resting bouts than those in the moderate or high illumination treatment. 5. In conclusion, rearing broilers under a 16 h L : 8 h D photoperiod with high daytime light intensity resulted in greater behavioural synchrony in the flock, with the potential to improve welfare by increasing uninterrupted resting behaviour during the dark phase.

Birds as Laboratory Animals

Abstract Birds are used for a variety of teaching and research purposes. While domesticated species like chickens, turkeys, and quail are probably the most frequently used birds, a range of species that vary widely in terms of their behavior and their husbandry and care needs may be kept. We provide an overview of some aspects of the anatomy, physiology, and behavior of birds, and address general aspects of avian care in the laboratory setting. These include housing, environment, nutrition, environmental enrichment, handling, transport, special management practices (sexing, identification, incubation, insemination, chick rearing), field studies, amelioration of pain and distress, and euthanasia. While there is a great deal of information about these topics available for poultry, there is much less for captive wild species, so individuals responsible for their care will need to consult relevant literature and experts to ensure that the needs of those species are met in the laboratory setting.

Lighting Programs for Broiler Chickens: Pre- and Post-Hatch Effects on Behavior, Health, and Productivity

Lighting can have important effects on the welfare of poultry, but there have been few studies of the optimal photoperiods or light intensities for broiler chickens. Birds are sensitive to light stimulation even as embryos, so both pre- and post-hatch lighting regimes could have an impact. We conducted two experiments to examine lighting effects on broiler health and behavior. In the first, broiler eggs were incubated under either complete darkness (0L:24D), complete light (24L:0D), or 12 hours of light and 12 hours of darkness (12L:12D); chicks were then raised under a 12L:12D photoperiod. In the second, chicks were raised under a 16L:8D photoperiod at one of three daytime illumination levels (dim to bright): 5 (typical commercial lighting), 50 or 200 lux. Treatment did not affect feed consumption, feed conversion, growth, mortality, or gait score. However, the eyes of both 0L:24D and 24L:0D broilers were significantly heavier at 5 lux. Activity rhythms were also affected: 24L:OD fed more during the 2 hours after the lights went on, and 5 lux were less active during the day. Broilers incubated under 0L:24D, or reared under 200 lux, were more fearful, as indicated by more intense wing flapping after being caught and inverted. In addition, 0L:24D broilers had more composite physical asymmetry, as assessed by differences in length and width of their toes and metatarsi, which is an indicator of developmental stress. These results demonstrate that providing light during incubation or brighter intensity light during rearing can have positive effects on broiler welfare without negatively affecting productivity.

Backyard flock production

Abstract Keeping backyard poultry, especially egg laying hens, has become a popular trend in the United States, and across the world. People who are interested in consuming local food with less of an environmental impact and better welfare for the animals are driving this phenomenon. Despite the desire for better welfare, these flocks face their own unique challenges. From a research perspective, backyard flocks are difficult to track and sample using random, unbiased methodology. However, what little research has been done shows that backyard flocks face welfare concerns related to health and disease transmission, poor access to veterinary care, and public health issues. Further research to understand these challenges, as well as the dissemination of quality information to flock owners, are much needed.