The most common eggs used in cooking are hens eggs. Others, for example, duck or quail eggs, are also used on occasions.
To test for freshness put the egg in a bowl of cold water, the freshest egg sinks to the bottom the stalest floats, intermediate states indicate degrees of staleness.
Store eggs in the fridge while being aware that as eggshells are porous they absorb odours around them - good if it's truffles, less so for pineapple. Eggs that have been lightly beaten can be frozen. If separated the whites can be frozen as is, yolks need to have a pinch of salt or sugar beaten in to stop them becoming too thick. Defrost overnight in the fridge. Use immediately.
In Australia dozen packs of eggs contain:
The Review of Layer Hen Housing and Labelling of Eggs in Australia by SCARM Working Group define the different housing conditions of laying hens.
Conventional Cages Typical cages as specified in the current Model Code of Practice for the Welfare of Animals - Domestic Poultry 1995 - i.e. they are required to provide a minimum of 450cm2 of floor space per bird which may be calculated including the space under the baffle. (Recently manufactured cages measure 50cm X 50cm and house five hens which allows 500cm2 unrestricted floor space per hen if there is no baffle and down to 400cm2 unrestricted floor space per bird if the cage has a 10cm baffle). Conventional cages do not provide hens with nest boxes, litter for foraging or dust bathing, or perches.
Barns Birds are on the ground and free to move about with access to litter as specified in the Model Code of Practice for ?deep litter? systems. RSPCA accredited barns must meet a higher standard, with reduced stocking density and limited flock size. Nest boxes are provided in barns.
Free Range Birds range outdoors and have indoor shelter for night or poor weather. Stocking densities are as specified in the Model Code of Practice for ?range? systems.
Organic This describes a production philosophy rather than a housing system. It utilises a free-range production system with a reliance on management practices for the control of pests and diseases rather than a reliance on substances.