Relationship between egg‐shell colour and two measurements of shell strength in the Vasca breed

Abstract

1. Egg-shell colour, egg specific gravity, shell thickness and egg weight were determined for 2080 eggs from three varieties of the Vasca, a Spanish brown-egg-laying hen. 2. Intermediate, positive and significant (P < 0·01) correlation coefficients were found between egg-shell colour and specific gravity (0·25), or shell thickness (0·21). There was a very high (0·84), significant (P < 0·01) correlation between the measures of shell strength. 3. Shell thickness was accurately predicted with both specific gravity and egg weight as independent variables (determination coefficient 0·74); eggshell colour did not explain any further variation. 4. All traits showed considerable departure from normality in the form of negative kurtosis (shell colour and specific gravity), positive kurtosis (shell thickness and egg weight), negative skewness (shell thickness) or positive skewness (egg weight). 5. Egg-shell colour, specific gravity and shell thickness were less in July, in old birds and in eggs laid in the morning. Differences in egg quality traits between the three varieties were not significant.

A Review of the Relationship between Eggshell Colour and Water Vapour Conductance

“…Whilst eggshell colour may reflect upon eggshell quality (Briggs and Williams, 1975;Campo and Escudero, 1984;Solomon, 1987) it does not reflect on shell strength, at least in domesticated species, (Solomon, 1987) although see Gosler et al (2011) for details of a study in wild birds. There have been relatively few studies that have examined the relationship between eggshell colour and water vapour conductance.…”

Eggshell Quality Comparison between Blue-Shelled and White-Shelled Eggs of Brown Tsaiya Ducks

“…Darker eggshells can enhance egg strength because pigment molecules confer resilience to the shell, and the pigments have a potential cushioning effect between the calcite crystals (Solomon, 1987;Burley & Vadehra, 1989. ); moreover, egg shell color is positively correlated with both shell density and thickness (Campo & Escudero, 1984;Hu et al, 2002). This viewpoint can be supported by the positive correlations between thickness and strength among the colored eggshells in this study.…”

QUALITY PARAMETERS IN EGGS OF LAYER CROSS Hisex Brown AS AFFECTED BY THE OVIPOSITION TIME

“…Здесь, на наш взгляд, есть определенное противоречие, поскольку, как известно, первое яйцо в цикле куры откладывают рано утром, а с увеличением порядкового номера снесение отодвигается на более позднее время суток (1). Кроме того, по утверждению многих авторов (25)(26)(27)(28), цвет яичной скорлупы положительно коррелирует с ее толщиной и прочностью, а эти показатели, как уже отмечалось (12,19), наиболее высокие у яиц, собранных в полдень или в конце дня, но не утром.…”