Exactly When Does the Egg Shell Form?

[Barry Natchitoches]

Exactly when in the egg laying process does the little hen cover the egg material with the protective egg shell covering?


I'm trying to figure out exactly what happened to my little girl, Patty a couple of nights ago, and need this information to try and figure out what happened.

 

[gryeyes]

The shell forming part of the process is the longest, as it takes about 19 of the 26 hours involved in "building" an egg. The very last thing that happens is the hen covers the egg with the barrier called the "bloom" over the eggshell, and that only takes a couple of minutes.

 

[ivan3]

Not sure how far down the rabbit hole you wish to travel.

So:

THE ABSTRACT (for other interested aficianados):

Secretion pattern, ultrastructural localization and function of extracellular matrix molecules involved in eggshell formation

Maria Soledad Fernandez, , Alejandra Moya, Luis Lopez and Jose Luis Arias
Faculty of Veterinary and Animal Sciences, Universidad de Chile and Center for Advanced Interdisciplinary Research in Materials (CIMA), Santiago, Chile
Received 10 April 2000; revised 26 September 2000; accepted 18 October 2000. Available online 19 February 2001.

Abstract
The chicken eggshell is a composite bioceramic containing organic and inorganic phases. The organic phase contains, among other constituents, type X collagen and proteoglycans (mammillan, a keratan sulfate proteoglycan, and ovoglycan, a dermatan sulfate proteoglycan), whose localization depends on a topographically defined and temporally regulated deposition. Although the distribution of these macromolecules in the eggshell has been well established, little is known about their precise localization within eggshell substructures and oviduct cells or their pattern of production and function during eggshell formation. By using immunofluorescent and immuno-ultrastructural analyses, we examined the distribution of these macromolecules in oviduct cells at different post-oviposition times. To understand the role of proteoglycan sulfation on eggshell formation, we studied the effects of inhibition of proteoglycan sulfation by treatment with sodium chlorate. We showed that these macromolecules are produced by particular oviduct cell populations and at precise post-oviposition times. Based on the precise ultrastructural localization of these macromolecules in eggshell substructures, the timing of the secretion of these macromolecules by oviduct cells and the effects on eggshell formation caused by the inhibition of proteoglycan sulfation, the putative role of mammillan is in the nucleation of the first calcite crystals, while that of ovoglycan is to regulate the growth and orientation of the later forming crystals of the chicken eggshell.

Author Keywords: Eggshell; Oviduct; Biomineralization; Type X collagen; Keratan sulfate; Dermatan sulfate; Mammillan; Ovoglycan

Corresponding author. Tel.: +56-2-678-5550; fax: +56-2-541-6840; email: [email protected]

Matrix Biology
Volume 19, Issue 8, January 2001, Pages 793-803

(full journal article that is more detailed: http://captura.uchile.cl/jspui/bitstream/2250/2379/1/Fernandez_MS.pdf (these Matrix biologists are trying to understand the precise deposition - at ambient temps. in order to develop a low cost substrate for circuits/potential templates for tissue repair, etc.)

More to the point, with day by day info is the GAM USDA Egg Grading Manual: http://www.ams.usda.gov/AMSv1.0/getfile?dDocName=STELDEV3004502

Excellent reference to the overall subject: http://people.eku.edu/ritchisong/avianreproduction.html​

 

[Arielle]

Now I do feel like I'm back in Poultry class at university!!!! Thanks for the refresher course!