Chickens lay eggs in what we call ‘clutches’, with an egg laid per day for a number of consecutive days followed by a rest period before they start to lay another clutch.
The average chicken clutch size is about 12 eggs, with a pause of roughly a day or so in between clutches. Clutch size and pause length can vary quite a bit between birds and is largely dependent on breed and the age of birds.
Genetic selection has meant that commercial laying breeds, such as the Shaver and the Hy-line, have become exceptional layers with large clutch sizes and short pauses. As birds get older, they start to lay less eggs per clutch with larger pauses in-between and their most efficient production period will be in their first year as a layer. This explains why we might not always get an egg a day out of our birds, especially as our flock ages. We may not even notice the difference in egg production between our old and young hens if we run a mixed-age flock.
Older chickens lay larger eggs but they deposit the same amount of calcium into the shell which means we tend to see more thin-shelled egg issues in an aging flock. Older birds also have weaker chalazes which are the ropey strands of egg white which anchor the yolk in place in the center of the egg. The weaker chalazes can give the whites of the egg a more ‘watery’ appearance once cracked. This issue is also linked to the freshness of an egg with older eggs similarly appearing watery.
So, what does this mean for the backyard flock? Well, we have to expect that egg production and egg quality will drop off for older hens, even if offered the best-quality layer feed. Keeping older birds to a ripe old age can be personally very satisfying however, if space is limited and you really want to maintain production and egg quality, it is best to have a replacement strategy in place so that you always have young birds coming through to replace your older ones each season.
Most backyard chook farmers will purchase young hens (pullets) at point of lay, while others might choose to incubate eggs and rear chicks themselves. If you choose to rear your own it is important to note that the first five weeks of life is critical for development of immunity and the digestive system. A high-quality chick starter can make all the difference when rearing chicks.
Reproductive tract development is critical for egg production and occurs around 15 to 25 weeks of age, so moving on from a chick starter to a well-balanced pullet grower feed can be beneficial and have lifelong benefits for your flock. If buying your pullets in at point of lay it is worth asking how old they are. Chickens will start laying at about 17 weeks of age, or slightly older for heritage breeds. If birds are already in lay when purchased, you may have missed a good portion of their most productive year.
It is not all about egg production with a backyard flock though. Many people enjoy keeping their older chickens around and are happy with a reduction in performance. It is more about figuring out what you want from your flock and having realistic expectations if you do have some older chickens in the mix.
For further information, contact your local Nutrition Specialist.
Article supplied by Stacey Cosnett, Nutritionist.