Eggs develop in the ovary, then detach and slip into the oviduct – a long tube that ends in the vent, or cloacae, through which they then exit the body. As the egg travels through the oviduct, it rotates continually within the tube, the movement twisting structural fibres called chalazae into rope-like strands that anchor the yolk in the white from opposite ends of the egg. Once a fertile egg has been laid, the chalazae act as a kind of shock absorber to keep the germinal disc of the yolk on the uppermost surface and therefore always nearest the point of incubation. This is why fertile eggs that have been transported must be given 24 hours to settle before incubation is attempted.

The hen’s oviduct has two parts: in the first, the white forms around the yolk; and in the second, the shell is made and the pigment of the shell is deposited. Each egg takes three to five hours to pass through the first part of the oviduct and a total of 15-20 hours before it is ready to be laid. While the colour of the shell has no relevance to the hatchability of an individual egg, its composition does and only perfect eggs should ever be considered for hatching. Avoid including any that are misshapen, the wrong colour typical for the breed, or those whose shells are chalky or lumpy in appearance or texture. Remember that if these eggs are included when collecting a clutch for incubation that, even if they do hatch, the progeny may well lay the same type of second quality egg, which could take several generations of future breeding before any improvement is achieved. 

The colour of the yolk is directly associated with the hen’s diet and health. A very pale yolk can indicate that the hen lives in overcrowded quarters, is underfed or lacks a source of greenstuffs, whereas a bird fed a diet rich in xanthophylls (the yellow pigment from the carotenoid group found in green leaves) will produce a darker yellow yolk. Occasionally, a hen may produce an egg with no yolk at all or one with a double yolk. These are both the result of unsynchronised production cycles, and usually occur t the start or end of a laying period. The so-called ‘meat spot’ in the egg is, in fact, a mall deposit of blood caused by the rupture of a blood vessel during its formation and is not, as is sometimes thought, an indication that an egg is fertile. On occasions, a cloudy looking white might be observed: caused by carbon dioxide that decreases over time as it escapes through the porous shell, it presence is therefore an indication that the egg is freshly laid.

All birds will lay a clutch of eggs before starting to incubate them, and a hen is no different in this respect – she is just more likely to continue laying all the time that her eggs are being removed daily and as a consequence, she thinks she hasn’t produced enough for a clutch. Certain breeds of chicken, in particular the Mediterranean varieties such as Leghorns and Minorca’s, have had their broodiness bred out of them but otherwise, if the eggs are left until a clutch is formed, the hen will go broody and lose her breast feathers in order to create the ‘brood spot’ necessary to warm the eggs and begin incubation. The embryo of a large fowl normally develops inside the egg for 21 days, whereas that of a bantam has a slightly shorter incubation period (normally about 19 days). It is important that the embryo doesn’t become stuck on one side of the egg, so the broody hen will turn her eggs several times a day.

Store eggs for hatching in a cool place and in egg trays, preferably on their sides rather than up-ended and turn them daily until sufficient have been collected to go either in an incubator or under a broody. I have always believed that eggs should never be stored for longer than a week if being incubated by incubator and no longer than 10-14 days before being placed under a broody hen – the fresher the egg, the better the chance it has of producing a strong healthy chick that hatches on time. Remember, however, not to set any eggs immediately they have been laid, as they first of all need to cool before setting. The egg’s porosity also makes it unwise to wash eggs unless absolutely necessary and where this is the case, a proprietary egg wash should be used.

Although unlikely to affect most Fancy Fowl readers, were you intending to keep large numbers of birds, or plan to sell your eggs anywhere other than from your own home, there are a number of regulations you must abide by. Some of these rules relate to food safety and egg traceability, while others are concerned with bird health. If you owned more than 350 hens, for example, you would need to be registered with the Egg Marketing Inspectorate and your eggs bear a date stamp and producer registration number: the eggs would also need to be graded by size. Anyone with less than 350 birds in their flock but who still wished to sell their eggs commercially and in premises away from home, would also need to stamp their eggs with a producer registration number and the eggs must be un-graded. Fortunately for most people reading this, you do not have to mark eggs sold at your gate or delivered by hand to your ‘customers’, but they must not be used in the catering industry. If you keep more than 50 birds of any breed, you have an obligation to include them in the Great Britain Poultry Register (owners with less than 50 birds are encouraged to register voluntarily). This is part of a programme set up by DEFRA to improve risk assessment and monitoring of avian influenza outbreaks.

If you are at a loose end over Easter why not indulge in a bit of ‘egg jarping’, or egg rolling? Egg jarping is a traditional Easter game where players tap each other’s eggs in turn until one breaks, the winner of each round continuing until there is only one egg left. Egg rolling makes far less mess, as the eggs are hard-boiled before being rolled down a hill to see whose goes the furthest.

Author: Jeremy Hobson

Jeremy Hobson writes a regular 'Poultry Advice' Column in Fancy Fowl Magazine

Article Reproduced with the kind permission of Fancy Fowl Magazine