INDONESIA VS UBEKISTAN (2 :0)PREDIKSI

A Look at Chicken Eyes

A Look at Chicken Eyes

Recognizing Marek's Disease Symptoms and Other Common Ailments

By Rebecca Krebs

As we watch our flocks busily foraging in the backyard, the importance of chicken eye health becomes obvious. Whether chasing grasshoppers or courting the ladies, chickens use their eyes for every aspect of daily life. Consequently, problems with these vital organs are detrimental to the birds’ well-being, and it is crucial to recognize the symptoms of trouble so that illness can be proactively treated. 

Healthy chicken eyes are bright, wide open, and free of discharge or swelling. Normal chicken eye colors vary according to breed and age, but the eyes should always be clear with black pupils of a regular, round shape. 

Normal chicken eye colors vary according to breed and age, but the eyes should always be clear with black pupils of a regular, round shape.

In contrast, some of the first signs that a chicken isn’t feeling well are a dull or sleepy expression and squinty eyes. Discoloration, discharge, inflammation, and discomfort often characterize chicken eye maladies. Immediately isolate sick chickens from the rest of the flock to stop disease from spreading, and work to promptly diagnose and treat illness. 

Marek’s Disease in Chickens

One of the most dreaded of chicken illnesses is Marek’s, an incurable viral poultry disease spread by feather dander. It is highly contagious and typically affects young chickens that are three to30 weeks old. Symptoms of Marek’s disease in chickens include blindness, leg paralysis, and tumors. 

While birds with paralysis die quickly, those with ocular Marek’s, the form that affects chicken eyes, may survive for some time if the other symptoms aren’t present. Ocular Marek’s disease symptoms are irregularly shaped pupils, gray or cloudy eyes, difficulty seeing, and finally total blindness in one or both eyes. A chicken’s owner may realize something is wrong when the chicken doesn’t respond to human approach, or when it has trouble picking up small food items. It has more difficulty eating, drinking, and navigating as the disease progresses. Since chickens exhibiting symptoms of any form of Marek’s suffer and eventually die, the most merciful option is to humanely euthanize them as soon as the disease is diagnosed. 

 

 

Left — Normal chicken eye. Right — Eye of a chicken with ocular Marek’s disease. Photo courtesy of the U.S. Department of Agriculture.

Practicing strict biosecurity and good animal husbandry is key to preventing Marek’s disease in chickens, as well as other infectious diseases. The U.S. Department of Agriculture’s Animal and Plant Health Inspection Service provides guidelines for an effective biosecurity plan. These resources are available at www.aphis.usda.gov/publications/animal_health/2014/pub_bioguide_poultry_bird.pdf. 

Once Marek’s disease gains entrance to the flock, it is difficult to eradicate because chickens that develop immunity to it are permanent, asymptomatic carriers that shed the virus and can infect other chickens. But don’t panic if Marek’s turns up. Most flocks have been exposed to a strain of it, and there are several options to control the disease. 

• Genetic Resistance: Chickens can develop hereditary resistance to mild strains of Marek’s within a few generations. This option is so effective in some situations that the flock experiences no losses to the disease after building resistance. Chicken breeders often choose this route to establish natural immunity in their birds. However, flocks infected with more virulent strains of Marek’s may need to be vaccinated. 
• Marek’s Vaccination: Vaccinating for the disease is a widespread and generally reliable means of control. You can opt to have your chicks vaccinated when you purchase from most hatcheries, and you can purchase the Marek’s disease vaccine if you decide to vaccinate your own chicks (chicks are vaccinated as day-olds). Vaccinated birds can shed the virus for life, so any new chicks should be vaccinated before entering a vaccinated flock. The use of these chicken vaccines is controversial because they are believed to be responsible for the increasing virulence of Marek’s disease. Some flock owners avoid vaccination unless necessary. 
• Complete Isolation: Chicken owners can control Marek’s by isolating vulnerable young chickens from all other poultry, including young poultry sourced from different producers. Since people and equipment easily convey feather dander between flocks, the quarantine must be extremely strict for this option to be successful. Thoroughly disinfect facilities between batches of chicks, as the Marek’s virus is infectious for at least a year after the birds leave the premises.