Classification and packaging of ecological eggs The laying hen is responsible for the greatest volume of eggs in the egg trade. The laying hen lays eggs regardless of whether they have been fertilized by a cock. Eggs (Figure 1 and 2) for consumption are normally unfertilized eggs produced by hens which do not live with a cock, and cannot, therefore, become a chicken after incubation. The ovule, which is the yolk, detaches itself from the ovary and, on its way down the oviduct; it becomes surrounded by the egg white and shell, especially conceived for its protection. Put simply, the parts of an egg are as follows: the shell, the white or albumen, and the yolk separated from each other by membranes which maintain their integrity.

The average weight of an egg is around 60 g, of which the white is 60%, the yolk 30% and the membranes and shell 10%. The composition of the egg can be observed in the presentation (Birds and Eggs, n.º 20, July/August, 2002). Starting in 2004 consumers were given more information regarding the production and origin of eggs. A Commission Directive (No. 1999/74/CE), of Jul 19 and the Commission Directive (No. 2002/4/CE), of Jan 30, regarding the labelling and marking of eggs is applied to all eggs for direct human consumption, including, therefore, ecologically produced eggs.

There are two quality categories for eggs: category A and category B Category A eggs are classified according to weight class: XL (extra large) equal to or over 73 g, L (large) 63 to 73 g; M (medium) 53 to 63 g and S (small) under 53 g. Starting Jan 1 2004 eggs will be stamped on the shell with a code (Figure ).

This information allows the consumer to choose eggs from various member states, ecologically produced eggs, open air eggs among others. The case of an egg classification and commercialization centre, “Casa do Aidro – Bernardino de Almeida e Costa & Filhos, SA,” located in Carvalhais, S. Pedro do Sul, Viseu Portugal, can be seen in the film. The chickens are ISA BROWN of the semi-heavy strain, with a heavy brown father and a light white mother.

The company has its own egg deposition centres. The semi-automatic category selection system, IRUS (infra-red-sound) System, which categorizes eggs based on infrared radiation. After egg classification by categories, there are scales which weigh each egg individually and place it in the corresponding box. Before put into the boxes, the eggs are stamped with the respective code as mentioned above. After this, the eggs are packaged, stored and placed on the market.