Understanding the dynamics of cage-free housing

When you move a bird that was primarily in cage systems to cage-free or outdoor access, they’re going to have more access to litter which can lead to a greater probability of issues such as coccidiosis. Coccidia are intracellular protozoan parasites that multiply in the intestinal tract leading to tissue damage. This damage can result in decreased nutrient absorption, dehydration, blood loss and increased susceptibility to other diseases, such as necrotic enteritis.

In a system where the birds have increased access to the litter and faecal material contaminated with coccidia, developing immunity to coccidiosis is even more vital compared with birds that would enter a caged system later in life. In terms of vaccination, appropriate cycling of vaccinal oocysts is important and depends on factors such as vaccine coverage and litter moisture.

Respiratory problems, parasites and worms

Respiratory problems may also increase. These issues are due, in part, to birds having greater exposure to faecal material and dust (litter access). As birds have greater access to litter and the ground outside, there is a greater chance of potentially being exposed to parasites and possibly cause worm infestations. Increased roundworm and even tapeworm burdens have also become more prevalent in these systems. Spotty liver disease, caused by Campylobacter hepaticus and C. bilis, is particularly prevalent in free-ranging flocks.

FUDS

Focal ulcerative dermatitis syndrome (FUDS) is associated more with cage-free layers and over time can lead to high mortality losses. This skin condition is unusual in that it is not necessarily connected with pecking, scratching or other wounds. Initially Staphylococcus hyicus was suspected to be the causative agent but more recent research has indicated that Staphylococcus aureus and Staphylococcus agnetis are the main bacteria found in these lesions. More cases of erysipelas have been noted this past year, probably due to the access to other animals, such as pigs or wildlife, that could be the source of the disease. Increased pecking – or any other external trauma – can also create a pathway for bacteria to enter the birds.

Health plan

These challenges mean that it’s important to have a proper layer health plan. The following points and considerations set out what this health plan should include.

• Vaccines – have an appropriate vaccination programme in place, plus coccidiosis control.
• Gut health – make sure you’re managing good gut health. This means using pre, pro and post-biotics. A better gut microflora is going to help decrease unwanted bacteria, increase the useful bacteria, and birds will potentially have fewer issues with intestinal diseases. Improving gut morphology is also important. It is a good idea to look for and incorporate an immune-support feed additive. This will help not only with immune function and gut health, but also overall well-being.
• Biosecurity – here you want to control people, equipment and anything that may introduce unwanted pathogens onto the farm or to the flock. Any equipment coming into the poultry house needs to be clean. There needs to be a good sanitation programme in place between flocks.
• Water sanitation and maintenance – it is critical to be aware of this, as pathogens can get into water lines and biofilms, which can lead to issues such as disruption of the microflora or dysbacteriosis. This can lead to birds getting infections and the need for treatment and antibiotics.
• Cleaning and disinfection downtime. You need to have a procedure in place and allow enough downtime before birds are moved back in.
• Rodent and insect control – any rodent/insect/foreign creature can bring in pathogens, causing more complications.

Welfare challenges

Unfortunately, cage-free challenges go beyond what is within the normal veterinary scope. One of the main welfare challenges we tend to see is feather and vent pecking. Pecking and subsequently, cannibalism, can start when one birds sees the shiny or reddened tissue around the vent and pecks at it. Once the birds see blood, they can zero in on this abnormal area, leading to more pecking. This cycle can lead to mortality.

With birds free to roam around, floor eggs can be a serious and labour-intensive problem. Photo: Henk Riswick

You need to work on management concerns and provide appropriate beak trimming. There are many factors that could be involved in feather pecking or feather eating, including whether the birds feel satiated, behavioural concerns, nutritional deficiencies, and others.

Another welfare challenge is birds piling. If layers are not properly trained to be used to people walking in and out of the barn, or if you do not stop them from piling in certain areas, this can lead to suffocation.

Genetics are another important factor when looking at which birds will fare best in a cage-free environment. Keel trauma and broken yolks are yet another welfare challenge. As birds age, they may be less able to jump from one perch to another or have reduced bone density, increasing their chances of trauma to the keel bone if they land on it.

Outside temperature, predators and puddles

Some other important factors to keep in mind pertaining to welfare challenges include nutrition, lighting, and environmental stimuli. If birds have outdoor access, they’re going to have greater contact with predators. Heat and cold stress are also common as no one can control the temperature outside. Any kind of stress like this is going to weaken their immune system and potentially lead to problems with diseases. With outdoor access, producers must be aware of puddles caused by rain. Bacteria can grow in this stagnant water and birds tend to drink it. A good rule of thumb is to fill in these puddles with soil. Make sure the birds have access to clean, fresh water daily. Cage-free birds also have more chance of encountering animals that carry diseases, such as raccoons, opossums and livestock. These too, are factors that you must control to help keep birds healthy and safe.

Production challenges

With cage-free setups, migration is a serious issue. Birds have the ability to go anywhere, and they will. Let’s say a bird wants to go to the top or bottom tier. Because of this, they won’t touch the middle, which can result in issues with egg laying there. Ultimately, you need to work out the best system and setup to control these problems.

Another issue is having the facility layout determine veterinary choices, such as the type of vaccine application. The increased difficulty in applying spray vaccines in a cage-free setup compared to a caged setup, can lead some operations to move in favour of water application of vaccines rather than spray vaccinations. Given the right equipment and help, spray vaccination can be done in less time and with greater efficacy than using the water route.

Floor eggs

With birds free to roam around, floor eggs can be a serious and labour-intensive problem. Ideally, we want birds to lay all their eggs in the nest. However, heated floors, increased litter depth and the layout of the system can lead to birds wanting to lay eggs on the floor. Floor eggs require more manual labour, and the eggs are often dirtier. You need to know how to train young layers to nest appropriately. Make sure the arrangement of the feeders, water lines, and perches doesn’t discourage birds from getting to their nesting area. You must help them to get used to their new environment and do so as quickly as possible, otherwise, you may encounter problems down the road. Just take the time to watch the birds and you will get a sense of what works best in your particular system.

Understanding the bird

As poultry producers continue to transition to more cage-free and outdoor access, it’s important to recognise these disease, welfare and production challenges. Using these pointers you can set up an appropriate care and management plan, and determine what to address when it comes to layer health. In the end, understanding the bird is the key to how to best manage and care for birds in these housing systems.

By Sheilena Durbin, DVM, Diamond V