The effect of hen size and diet nutrient density during early lay on egg production (EP) at 24 and 69 wk of age (WOA) and late lay egg quality and hen health was evaluated. Based on bodyweight (BW) at 18 WOA ISA Brown hens were assigned as heavier (HW; n = 120) or lighter weight (LW; n =120). Sixty birds from each BW group were fed an early-lay diet of higher nutrient density (HND), or lower nutrient density (LND) between 18 and 24 WOA. From 25 WOA all hens received the same early-lay diet and then from 40 WOA the mid-lay diet. Hen average daily feed intake (ADFI), hen-day EP, egg weight (EW), egg mass (EM), and feed conversion ratio (FCR) were assessed at 24 and 69 WOA. Between 66 and 70 WOA eggshell and internal egg quality was evaluated and at 70 WOA BW, liver and bone health were assessed. At 24 WOA BW was highest in HW birds and birds receiving the HND diet (P < 0.01). Concurrently ADFI, and FCR were higher and hen-day EP was lower in HW compared to LW birds (P < 0.05). The HND diet resulted in lower ADFI and FCR at 24 WOA, but higher EW and EM compared to the LND diet (P < 0.01). At 69 WOA HW birds had higher ADFI, EW (P < 0.02) and heavier 70 WOA BW compared to LW hens. The lower FCR of the LW birds at 69 WOA was approaching significance (P = 0.054). Hen weight and diet density did not affect 69 WOA egg production. Between 18 and 69 WOA cumulative FI and EM were higher in HW hens (P < 0.01) than LW hens, as was cumulative FCR (P = 0.053). Hen weight and diet density did not alter 66–70 WOA internal egg quality, but the HND diet generated thicker eggshells and higher eggshell breaking strength (P < 0.05). Seventy WOA liver health, keel curvature and femur breaking strength did not differ. Overall LW hens had lower FCR than HW hens and the early-lay HND diet facilitated improved eggshell integrity during late lay compared to the LND diet.
The egg production (EP), egg quality and health of heavier or lighter hens fed a diet of either higher nutrient density (HND) or lower nutrient density (LND) during early lay, was assessed at very late lay. Based on their body weight (BW) at 18 wk of age (WOA) ISA Brown pullets were allocated as either heavier weight (HW; average 1.65 kg) or lighter weight (LW: average 1.49 kg). Half of each BW group received the HND (2,901 kcal/kg; 17.6% crude protein (CP) or LND (2726 kcal/kg, 16.4% CP) diet from 18 to 24 WOA. From 25 to 90 WOA all birds received identical early, then mid and late-lay diets. Hen BW was measured after peak-lay (36 WOA) and at 90 WOA. At 89 WOA and across 18 to 36 and 18 to 89 WOA feed intake (FI), EP, egg mass (EM), and feed conversion ratio (FCR) were calculated. Eggshell quality, breast score, relative ovary weight and liver and bone health were evaluated in very late lay. Differences in BW continued to 90 WOA. At 36 WOA HW hens produced heavier eggs, and had higher 18 to 36 WOA cumulative FI, EM (P < 0.001) and FCR (P < 0.05). When 89 WOA HW birds consumed more feed (P < 0.001) but EP, EM and FCR did not differ from LW hens. Cumulatively, 18 to 89 WOA FI and EM were higher for HW hens (P < 0.05), but cumulative EP and FCR was not different. The early-lay HND diet improved very late lay eggshell thickness (P < 0.05) and shell breaking strength (P = 0.05). Lighter hens fed HND and HW hens fed LND diet produced heavier eggs, higher relative oviduct weight and lower liver lipid peroxidase in very late lay (P < 0.05). Bone strength did not differ, but LW hens had higher femoral manganese and zinc (P < 0.05), lowering their likelihood of osteoporosis. Overall LW hens sustained EP throughout a longer laying cycle with beneficial bone characteristics. The HND diet improved eggshell strength and, in LW hens reduced hepatic oxidation.
The Australian and global chicken meat industries have benefited from rapid improvements in the efficiency of chicken meat production that have been predominantly achieved through genetic selection, optimisation of bird nutrition and improved bird health. However, this has also resulted in morphological changes in the bird with an increase in the prevalence of leg health disorders. Compromised leg health can cause pain and lameness and bodes poorly for bird wellbeing, bird mortality, and economic returns. There are also implications for the consumer who is increasingly mindful of animal welfare and is demanding more welfare friendly products. Accurate on-farm assessment of bird leg health has challenges due to the diversity of leg disorders and the variety of techniques used to assess their severity and impact. Overall prevalence of leg disorders shows great variability between properties (farms) and flocks. Opportunities to improve bird leg health have been the focus of considerable research which has frequently included an evaluation of environmental enrichment as a means to reduce lameness and improve bird mobility. To this end, currently in Australia, 78% of chicken meat is produced under the conditions of the Australian RSPCA Approved Farming Scheme, which requires perches in the birds’ environment. However, the value of perches in providing enrichment and improving bird welfare is unclear. Therefore, this review explores animal welfare and consumer attitudes towards meat chicken welfare, describes leg disorders, outlines techniques for assessing leg health and discusses opportunities to enrich the birds’ environment to improve bird mobility and leg health.
This study compared the impact of a higher nutrient density (HND) or lower nutrient density (LND) diet fed during early lay to either heavier weight (HW) or lighter weight (LW) ISA Brown hens. At 18 wk of age (WOA) pullets (n = 240) were evenly assigned to either HW (n = 120) or LW (n = 120). Sixty birds from each weight group were then randomized to either the HND or LND diet treatments which were fed from 18 to 24WOA inclusive. At 25WOA the LND diet replaced the HND diet. All hens remained on LND diet to 50 WOA. Hen performance was measured from 18 to 50 WOA. Femur and liver health were evaluated at 50 WOA. Egg quality was assessed from 46 to 50 WOA. The 18 WOA HW hens had higher BW, cumulative egg production, cumulative feed intake (CFI), and cumulative egg mass (CEM) to both 24 and 50WOA (P < 0.01). At 24WOA the HND diet also generated higher BW (P < 0.001), CEM (P < 0.001) and lower cumulative feed conversion ratio (CFCR) (P < 0.01), the latter being sustained to 50 WOA (P < 0.01). At 50 WOA CFCR of LW birds was lower than HWbirds (P < 0.01). Egg weight (EW), yolk diameter, and percent yolk weight were higher (P < 0.05) in the HWbirds with the highest albumen to yolk ratio in LW birds (P < 0.05). Egg shape index was higher in LND diet fed birds (P < 0.01) while LW hens had higher shell phosphorus (P < 0.05). Body weight and diet nutrient density interacted on femoral diameter and cortical thickness being higher (P < 0.01) in LW birds fed HND than LW birds fed LND diets. Fatty liver hemorrhagic scores (P < 0.05) and liver lipid peroxidase (P < 0.001) at 50 WOA were higher in HWand LND diet treatments. Concurrently HW birds had the highest CFI and EW while CFCR and liver health were superior inLW and the HND diet treatment.
The study objectives were to understand the practices and perceptions of sheep farmers and district veterinarians (DVs) towards sheep health management and, the impact of disease at the farm level in addition to the availability, accessibility, and use of veterinary services. Data were collected using question-based surveys, distributed online and in-person to sheep farmers (45 respondents) and DVs (25 respondents). Most farmers were male, ≥51 years old, who placed a high priority on the health and welfare of their sheep. For disease prevention most farmers vaccinated their sheep (91%) and 86.7% had a farm biosecurity plan, although its components and their application varied, e.g., the isolation of new or sick sheep. Fencing costs were most frequently identified (70.5% respondents) as a financial concern for sheep farmers. Their most common sources of information about disease control and prevention were DVs (66.7%), private veterinarians (60.0%), the internet (42.9%), rural suppliers (35.7%), and farmers/neighbours (28.6%). Fifty-eight percent of farmers reported a long distance from veterinarian services. Farmers preferred to receive information via email (77.8%), whereas 56% of DVs preferred to share information via phone call. This discrepancy presents an opportunity to align these mechanisms more closely for effective dissemination of information and increased producer engagement.
Spotty Liver Disease (SLD) is a serious problem in laying hens farmed in cage-free systems. The causative organism, Campylobacter hepaticus, is regarded as having a fecal-oral method of transmission and hence may build up and spread readily in housing systems which allow ease of direct contact of hens with the flock's fecal material. The epidemiology of SLD has not been thoroughly investigated. An initial cross-sectional analytical epidemiological survey of SLD in free range and barn layer systems was conducted in Australia over 2019 to 2021.The survey involved rearing flocks (n = 32) which were then followed through into laying flocks (n = 24) up to 40 wk of age. Cloacal swabs were collected during rearing and lay for C. hepaticus detection by PCR. Flocks were classified as "Cases" (n = 18) where clinical SLD according to the case definition was observed or "Controls" (n = 6) which were clinically unaffected. No C. hepaticus was detected in cloacal swabs from rearing houses whereas the organism was detected in 18 Case flocks in lay and from 2 Control flocks in lay. All layer houses that incorporated a scratch area (n = 13) were categorized as Cases. Thus, having a scratch area is a key determinant for SLD and no analyses of further contributory factors from these flocks were able to be made. Of the remaining 11 flocks which had floors fully covered by slats, 5 were Cases (45%). Further risk factor analysis was compromised by this small sample size and identification of other significant associations was not possible. A larger survey investigating flocks laying in houses with fully slatted floors was undertaken to further the understanding of SLD epidemiology and is reported in a companion paper.