Effects on egg production and quality of supplementing drinking water with calcium and magnesium

This study was conducted to appraise the effects on egg quality and production performance of laying hens when drinking water was supplemented with calcium (Ca) and magnesium (Mg). A total of 384 (64-week-old) Hy-line Brown laying hens were assigned at random to four treatments, which consisted of CON: unsupplemented drinking water; T1: drinking water + 2 mg/L Ca + 250 mg/L Mg; T2: drinking water + 4 mg/L Ca + 510 mg/L Mg /10 L; and T3: drinking water + 5 mg/L Ca and 760 mg/L Mg. The experiment lasted six weeks. Water intake increased linearly in week 1 with the rising levels of Ca and Mg in the drinking water. Increasing the Ca and Mg levels improved eggshell strength (week 2 (P =0.01), week 5 (P =0.01), and week 6 (P = 0.03), and eggshell thickness (week 6) (P =0.02) and reduced the rate at which eggs were broken (week 4) (P =0.01). The supplemental Ca and Mg did not affect egg production, egg weight, Haugh unit, albumen height, eggshell colour, and yolk colour compared with CON. Nor did they influence the Haugh unit and albumen height after storing for 1, 5, 10 and 15 days. In conclusion, adding Ca and Mg to the drinking water increased the thickness and strength of the eggshells.

UK consumers' willingness to pay for laying hen welfare

PurposeThis study investigates UK consumers’ perception and willingness to pay (WTP) for egg attributes associated with laying hen welfare, namely with beak-trimming practices and injurious feather pecking (IP). The aim is to examine any change in WTP after improved consumer awareness.Design/methodology/approachBuilding upon existing literature, the authors designed an online survey in which the method of discrete choice experiment (DCE) was employed. The study includes two identical DCEs with the second being introduced after respondents were presented with an educational excerpt about beak-trimming practices, on farm IP occurrence and the docile nature of white egg laying hens – reducing IP.FindingsThe mixed logit regression model demonstrated that consumers' WTP for egg attributes associated with beak trimming and IP decreased in the second DCE (12.6% for organic and 2.55% for free-range). For eggshell colour, the analysis revealed a shift from a preference to brown eggs to indifference between eggshell colours.Originality/valueOverall, UK consumers have a preference in higher hen welfare resulting in a decrease in WTP once they are aware of welfare losses in current systems; however, more insights are required in terms of the promotion of white shelled eggs as a means of reducing IP on UK farms.

Yield Performance, Laying Behaviour Traits and Egg Quality of Purebred and Hybrid Hens Reared under Outdoor Conditions

This study compared the yield performance, laying behavioural traits and egg quality of purebred and hybrid hens (from 28 until 44 weeks of age, considering four periods) reared under outdoor conditions. The four genotypes were reared on the same trial station, on four areas (one genotype/area), and under the same environmental conditions from hatching until the end of the trial. Italian dual-purpose purebred (Ermellinata di Rovigo—ER and Robusta maculata—RM) and hybrid (Hy-Line Brown—HB and Hy-Line White 36—HW) hens (flock size: 70 birds/genotype) were allowed outdoors (4 m2/bird, good pasture during the growing period and poor pasture throughout the laying period, according to the season) and indoors (0.20 m2/bird, five birds/individual nest) and fed commercial feed. Significant (p < 0.01) differences among genotypes were found. The hybrids showed a higher laying rate and hen-day edible egg mass, and a lower body weight than the purebreds. Broken and out-of-nest egg% were higher in RM and HW than ER and HB, respectively. Double-yolk egg% was higher in hybrids than in purebreds. The eggshell colour varied among brown eggshell ER, RM, and HB. The ER showed the lowest shape index. With aging, the yolk to albumen ratio linearly increased in all groups, eggshell% changed in ER, HW, RM (cubic) and in HB (linear). The purebreds showed meat spots% higher than blood spots; HW showed the lowest total inclusion%. In conclusion, according to an egg scoring evaluation (egg weight = medium-large size, yolk to albumen ratio = 0.5, total inclusions = none), HW showed a higher quality than HB and RM, and ER was intermediate. The RM hens showed the highest% of defective eggs, especially for overcrowding at nest, HB showed the lowest. Under outdoor conditions the laying behaviour of the purebred hens and the nest management are important factors for the saleable egg rate.

The Impact of Eggshell Colour on the Quality of Table and Hatching Eggs Derived from Japanese Quail

The aim of the study was to evaluate table and hatching eggs of Japanese quails (Coturnix coturnix japonica) depending on the eggshell colour. The research was carried out in two stages, in terms of table eggs’ quality and their biological value as hatching eggs depending on the eggshell colour. In both stages, 300 Japanese quail eggs were used in each (600 in total) divided into two equal groups: with a brown-spotted shell, with a uniform shell in shades of blue. In the 1st stage, quality characteristics of the whole egg (weight, specific gravity, proportions of particular elements), yolk (weight, colour, index), albumen (weight, height) and shell (colour, strength, weight, thickness, density) were evaluated. In the 2nd stage, eggs were incubated under standard conditions and following biological characteristics were analyzed: eggs fertility, embryo mortality, hatchability of fertile and set eggs, body weight of hatchlings and their proportion in egg weight. The shell colour, “blue” or spotted, of Japanese quail eggs, does not appear to influence their quality if they are intended for consumption. However, the hatching results and body weight of obtained chicks of Japanese quail may be affected by the eggshell colour.

Response of three laying hen genotypes to two feed calcium levels

The present study aimed to evaluate the effect of two dietary Ca levels (3.00% vs 3.50%) in three hen genotypes (ISA Brown, Bovans Brown and Moravia BSL) on their laying performance and quality of their eggs. In order to evaluate the response to dietary Ca, an experiment was conducted with 300 laying hens. One hundred birds from each genotype were divided into 10 replicates (10 birds/cage/Ca level). To reveal the differences, the following characteristics were measured: hen-day egg production percentage, daily feed intake, egg weight, albumen and yolk weights, Haugh unit, eggshell colour, eggshell weight, eggshell thickness, eggshell strength, egg shape index and eggshell index. A higher Ca level significantly increased the hen-day egg production percentage of Bovans Brown and Moravia BSL, while ISA Brown laying hens had the higher egg production percentage at a lower dietary Ca level (85.97% vs 82.41%). No significant effect of dietary Ca level was observed on any internal egg quality measurements except the Haugh unit. However, the dietary Ca level significantly affected some of external egg quality measurements, namely eggshell colour (P &lt; 0.001), eggshell weight (P = 0.003) and eggshell strength (P = 0.012). The results of the present study show that laying performance and egg quality parameters responded differently according to hen genotype and dietary Ca level. Bovans Brown and Moravia BSL laying hens required higher levels of Ca to keep egg production high, while the eggshell quality measurements were better at the lower dietary Ca level. Thus, it is recommended to adjust the Ca levels in feed to the nutritional requirements of laying hens.

Temperature drives the evolution and global distribution of avian eggshell colour

The survival of a bird’s egg depends upon their ability to maintain within strict thermal limits. Avian eggshell colours have long been considered a phenotype that can help them stay within these thermal limits, with dark eggs absorbing heat more rapidly than bright eggs. Although long disputed, evidence suggests that darker eggs do increase in temperature more rapidly than lighter eggs, explaining why dark eggs are often considered as a cost to trade-off against crypsis. Although studies have considered whether eggshell colours can confer an adaptive benefit, no study has demonstrated evidence that eggshell colours have actually adapted for this function. This would require data spanning a wide phylogenetic diversity of birds and a global spatial scale. Here we show evidence that darker and browner eggs have indeed evolved in cold climes, and that the thermoregulatory advantage for avian eggs is a stronger selective pressure in cold climates. Temperature alone predicted more than 80% of the global variation in eggshell colour and luminance. These patterns were directly related to avian nesting strategy, such that all relationships were stronger when eggs were exposed to incident solar radiation. Our data provide strong evidence that sunlight and nesting strategies are important selection pressures driving egg pigment evolution through their role in thermoregulation. Moreover, our study advances understanding of how traits have adapted to local temperatures, which is essential if we are to understand how organisms will be impacted by global climate change.

Unscrambling variation in avian eggshell colour and patterning in a continent-wide study

The evolutionary drivers underlying marked variation in the pigmentation of eggs within many avian species remains unclear. The leading hypotheses proposed to explain such variation advocate the roles of genetic differences, signalling and/or structural integrity. One means of testing among these hypotheses is to capitalize on museum collections of eggs obtained throughout a broad geographical range of a species to ensure sufficient variation in predictors pertaining to each hypothesis. Here, we measured coloration and patterning in eggs from 272 clutches of Australian magpies ( Cracticus tibicen ) collected across most of their geographical range of ca 7 million km 2 ; encompassing eight subspecies, variation in environmental parameters, and the presence/absence of a brood parasite. We found considerable variation in background colour, as well as in the extent and distribution of patterning across eggs. There was little evidence that this variation was explained by subspecies or the contemporary presence of a brood parasite. However, measures of maximum temperature, leaf area index and soil calcium all contributed to variation in egg appearance, although their explanatory power was relatively low. Our results suggest that multiple factors combine to influence egg appearance in this species, and that even in species with highly variable eggs, coloration is not readily explained.