Most poultry farmers in Kenya are practising the deep-litter system of farming.
This involves keeping birds on the floor with wood shavings as bedding material. However, recently, farmers are shifting to battery cages (metal or wire enclosures used to house laying hens). Here are the pros and cons of the two systems.
The initial cost of establishing poultry units in a cage system is higher than in a floor system.
Most layer farmers rear their birds on the floor from day one. If you want to turn an ordinary floor system into a battery cage system, you will spend an additional Sh350 per bird on cages.
This means that a farmer will have to sell more eggs to recoup this extra cost. Living space is one of the most controversial topics in the battery cage system. A chicken is given space depending on the bird’s size, cage design, and management system. Most common commercial layers in cages are given 450cm2 per bird.
Each compartment measures about 60cm deep X 45cm high X 120cm long, carrying 4-5 hens per compartment.
So, for a floor size of 300 square metres, in a cage system, you can keep between 6000-8000 layers, while on the same size on a deep litter system, you can manage only 1,800-layer birds.
More chickens can then be kept in this system compared to the floor type. Ethologists, however, disagree; they say the chickens are denied the ability to stretch, freely turn without touching each other, flap their wings, or scratch the floor and nest. In countries where animal welfare is taken seriously, governments have passed legislation to ban battery cages altogether because the cages do not provide freedom from discomfort, expression of normal behaviour and freedom from fear and distress.
It has been proven that chickens in cages tend to have higher longevity, have less manure-borne infections, suffer less cannibalism, worm infestation, feather, and vent pecking and are less aggressive.
It is easier to pick out sick birds in a cage for treatment. On the flipside, birds in cages do not exercise enough and, therefore, suffer from fractures of both long and keel bones towards the end of production, a condition referred to as osteoporosis.
Physical restrictions cause differential rates of freedom from social conflicts in favour of birds in cages. Farmers have encountered lower mortality in cages compared to the cage-free floor system by a difference of 1-2 per cent.
Battery cage floors are designed in a sloppy way that allows eggs to roll to the front of the cage as soon as they are laid.
The eggs are, therefore, cleaner and have a longer shelf life than in a deep-litter system, where floor eggs tend to go bad within a few days of storage.
Distribution of feed in the cage system is also faster with little spillage compared to the deep litter system.
In the latter, birds will scramble during feeding and spill feed in the litter. There is more competition for feed and water space in the floor system, creating less stable social groups. This could lead to behavioural problems like feather pecking and piling.
Since cage farming is highly intensive, 10,000 birds can be easily managed by one individual, as feeding, water supply are all automated.
The poultry worker’s job is to collect eggs and remove any dead birds from the cage. It requires less animal health and production knowledge.
In a deep litter floor system, biosecurity can easily be breached, especially during visitation by contaminated, dirty feet and clothing.
In a battery cage system, the single biggest problem is the removal of raw chicken droppings. It is very laborious, and in situations where there is a delay in removal, ammonia gas generated can cause damage to the eyes and respiratory linings. Poultry manure is an ideal medium for fly reproduction. In a cage system, the fly menace is a big issue.
[Dr Messo is the company veterinarian, Kenchic; watsonmesso@yahoo.com]
