The egg can be considered as a primary “capsule of life”, in which all ingredients are included in precise amounts necessary to sustain the development of an embryo and give rise to birth of a healthy chick. Thus, the chicken eggshell (CE) contains ions and compounds that are necessary to generate new life, serving as a building material of the new organism. Therefore, it is not surprising that...

Individual variation in life-history trade-offs can be caused by differences in quality and age. We tested for individual variation in parental investment in incubating tree swallows (Tacyhcineta bicolor) subjected to a feather-clipping manipulation. Individual quality influenced how females were affected by feather clipping; lower quality clipped females showed a greater reduction in incubatio...

The hypothesis was tested that increased partial pressure of oxygen during the plateau (25 to 26 d of incubation for turkeys) and paranatal (27 to 28 d of incubation) stages of incubation may increase survival rates of turkeys from selected genetic lines. Partial pressure of oxygen inside the incubator cabinet was increased to 171 + 3 mm Hg of the barometric pressure during the plateau stage in...

Egg turning behavior is an important determinant of egg hatchability, but it remains relatively understudied. Here, we examined egg turning rates and egg temperatures in Forster's terns (Sterna forsteri). We used artificial eggs containing a data logger with a 3-D accelerometer, a magnetometer, and a temperature thermistor to monitor parental incubation behavior of 131 tern nests. Overall, adul...

—Two cases of prolonged incubation by White Storks (Ciconia ciconia) were observed in the same nest in 2009 and 2010 in southwest Poland. Incubation lasted at least 59 and 65 days, respectively; i.e., 84 and 103% longer than the average incubation period. Extended incubation was accompanied by other abnormal breeding behavior. The lack of observed copulation in either breeding season, an extrem...

Egg productivity is the most important economic trait in egglaying poultry. Endocrine and environmental factors such as length of photoperiod and feeding allowance can influence egg production [1]. However, a genetic factor would be a prerequisite. Egg production is a polygenic inheritance trait with low to moderate heritability depending on the period involved, a major opportunity for improvem...

In bird species where males incubate but are smaller than females, egg size may be constrained by male body size, and hence ability to incubate the eggs. Using data from 71 such shorebird species, we show that egg size decreases as the degree of female-biased sexual size dimorphism increases, after controlling for female body mass. Relative egg size was not related to mean clutch size. However,...

The viability of freshly laid avian eggs declines after several days of exposure to ambient temperatures above physiological zero, and declines occur faster in tropical than temperate ecosystems. Microbial infection during preincubation exposure has recently been shown as a second cause of egg viability decline in the tropics, but whether microbial processes influence the viability of wild bird...

Embryonic development is a dynamic process that requires a fine balance between several factors in order to achieve an optimum hatchability and chick quality. These factors include the background of the embryo, such as genetic line of the breeders, the age of the breeder, egg weight, and factors related to the environment in which the egg is stored and incubated, such as temperature, humidity, ...