Cage Eggs and Energy

I picked up this interesting piece of information.  It comes from a 2007 research report.


Adrian Williams, senior research fellow at Cranfield University recently carried out a DEFRA-funded project that calculated the life cycle assessment (LCA) of different farming systems. The concept looks at the consumption of natural resources such as minerals and fossil fuel. "Poultry is the market winner in energy performance," said Dr Williams. "The sector should give itself a pat on its back." However, Dr Williams stressed that Global Warming Potential (GWP) varied depending on the different types of poultry farming methods. If the egg industry was to move towards all cage production, GWP would fall by 10% while going all free range would increase it by 10%. More significant is that going organic would result in a 40% increase in GWP. He explained the main reason was that organic chickens use more energy, having a lower feed conversion, so they eat more feed. Feed accounts for most of the energy required and is a key driving factor for poultry. With meat, organic also comes out worst because of the longer life-span of birds, again leading to a greater lifetime feed consumption.

 Put in language I can understand it means " eat a cage egg and help save the world ".  I guess it comes down to human population increase.  If we continue at our present rate there will be standing room only for ourselves and the chooks.

I Love Cage Eggs

I love cage eggs because I know they should be clean and fresh and laid by healthy happy hens. I always go for the cheapest cage eggs because they usually have the fastest turnover so most likely are the freshest on the shelf.

Gallus gallus ( the domestic fowl ) has been around a long time i.e. the domesticated variety. They have a similar range of varieties as the domestic dog except much more colorful. From the tiny bantam to the giant meat bird cockerel - all shapes and sizes.
Cage hens as a selected genetic variety has only been around since about 1960 or later. The farmer put his free ranging chickens in his new cages. He got more eggs and used less food but got a lot of new problems as well. The hens were nervous and didn't like to be too close so fighting broke out with vent pecking a problem.
The farmer wasn't going back to his old ways so he changed his stockmanship to adapt to the new method. Beak trimming was introduced to prevent vent pecking. Optimum stocking densities were worked out. Cooling systems to counteract heat waves and closing sheds to keep them warm was adopted.

The most important development in my opinion was the specific breeding of traits into the bird to help it adapt to life spent in a reduced area. Hens are now much more placid - they don't want to fight as much. Less energy is spent jumping around - no doubt the instinct to dust bath and flap their wings can be bred out as an unnecessary activity for a life spent free of parasites. The ability to change the hen by selective breeding to suit life in a cage is in no doubt - one only has to look at the pekinese breed of dog to realize the power of selective breeding - hard to believe its ancestor was a savage wolf.

Cage Hens and internal parasites

Cage hens don't have access to their droppings so the cycle of parasitic worms is broken as the hen will need to consume the worm egg from it's own or another hens droppings for the parasitic worm to hatch in the gut and begin it's life cycle again. In nature a small group of jungle fowl range over a large area so worms are in low concentrations and tolerable.
Once confined for egg production the worm burden builds up and needs to be treated unless the hen is kept off the ground. Provided there is sufficient room to room around and socialize with their mates the hen seems to be happy and rewards the farmer with the highest egg laying rate of any production system.

Cage Eggs and the Environment

Cage eggs are 20% better for the environment on an energy basis than other production systems. This means less food or energy is needed to produce the eggs as the hens don't need to search out the food or interact with other hens to get their share.

Hens like to be cool in the summer and warm in the winter. They seek shelter from the rain and a cool spot when its hot. High temperatures for extended periods as experienced in Australian heatwave conditions can be fatal to the domestic hen as its ancestors came from the cool jungles of Asia where small groups scratched around on the cool jungle floor. Being in a small group in an air conditioned cage with access to water and food must seem like an ideal situation to lay an egg.

Cage Eggs

Caged hens spend their relatively short lives of eighteen months confined to a cage from the time they hatch to the time they leave the laying shed. The reason for the short productive period is purely economic as once the hen has fulfilled one annual egg laying cycle it needs to rest and regenerate the laying organs. The cost of feeding and housing the hen while it's resting is greater than the cost of raising a pullet and an adult hen usually produces less eggs and bigger eggs in its second year.

Caged hens have continual access to fresh water through a drinker nipple attached to the cage. Water is essential for good egg production. A properly balanced diet is fed fresh several times a day using automatic feeders. This stimulates the hen to take an interest in the feed arriving to check for its favortite bits which aids egg production. Importantly each hen is part of a small group within the cage which allows it to socialize in a way similar to chickens in the wild from which it is genetically derived.

Many egg producers like to keep their hens in cages because they can manage them better for diseases. Its easier to pick a sick hen from a group of six than a group of hundreds. Seperating the hen from the group is simple in a cage but catching a hen from a large flock is stressful and can lead to injury and a drop in egg production.

Hens can be very savage at times if they sense a weakness in one of the flock. With many hens picking a weak bird the end often comes before the farmer can intervene. Small flocks in a cage reduce these occurances.