Occasionally chickens can either hatch blind or without eyes, or can go blind as a result of disease or injury to one or both eyes. Like with people, blindness can make things more challenging, however there are many blind chickens which are able to live happy, healthy lives. Chickens that are born with or acquire disabilities should not be so quickly cast aside---as there are many people who have kept and continued to care for chickens with blindness who have found it to be an extremely rewarding and worthwhile experience. Notable examples of successful cases involving blind chickens include:
- Mumble the chick born without eyes
- One couple, described their experiences with a blind chicken in a New York Times article, titled, 'What a Blind Chicken Can Teach Us About Humanity', authored by Ellen Chase. She and her husband discovered their chicken was blind when they noticed it start to bump into things and later found the chicken to always have a companion sitting by her side. This companion chicken would selflessly find worms for the blind chicken, help provide comfort, and protection. The couple later came to find that the entire flock of chickens even defended the blind chicken against unjust bullying from disgruntled flock members.
- Hildy the blind hen: Hildy's caretaker learned of Hildy's blindness by noticing that the hen would remain in the coop while the other flock members would free range in the pasture. Although Hildy knew and would come running to the sound of her caretaker's voice, when she arrived she couldn't see to react to the sunflower seeds being thrown out for the flock to eat as a treat. Her caretakers worked with her, and were able to successful train her to realize that when called for treats, she could too enjoy sunflower seeds by seeking out her caretaker's hands. More information about Hildy and how Hildy was trained can be found here.
- The Blind Chicken: This little chicken is a six-year-old Americana that was found blind at the age of three. She suddenly appeared with cloudy eyes and was observed running into things and seemed 'not quite right' by her caretakers. Her caretakers found that the other flock members would watch out for her and even maintained high placement in the flock's pecking order for a period of time. Read about her adventures found in a blog article titled 'The Blind Chicken', on her caretaker's website, found here.
Diseases associated with blindness in chickens include:
How to tell if a Chicken is Blind
- Avian encephalomyelitis: Avian encephalomyelitis (AE) is an important infectious disease affecting young chicks that is reported to be fairly common in backyard chickens. The disease is caused by the picornavirus, avian encephalomyelitis virus (AEV). Chicks that recover from AE have an increased risk of developing cataracts later in life resulting in blindness in one or both eyes.
- Marek's disease: Marek’s disease is one of the most common diseases found in backyard chicken flocks worldwide. MD is caused by Marek's disease virus (MDV), or Gallid herpesvirus 2 (GaHV-2) and presents as several different forms. One form, referred to as the Ocular (eye form), can cause chickens to develop gray, often misshapen, shrunken or unequally-shaped pupils that progress to blindness in one or both eyes.
- Chronic sinusitis: Chickens which develop chronic sinusitis (inflammation of the infraorbital sinuses) have a high risk of developing 'sunken sinus' which is where the globe of the eye retreats into its socket, giving the chicken the appearance of 'losing its eye', which can often result in blindness without proper treatment.
One of the most obvious, externally obvious clinical signs that a chicken is likely blind is the appearance of a gray or bluish cloudy eye color and irregularly shaped pupil. When only one eye is affected, the pupils are often different sizes as well. A quick and easy test that can be performed, to check whether a chicken is blind, is to slowly (don't use rapid movements because otherwise they can feel the airflow and sense the motion) move your finger towards the affected eye. A chicken that does not blind or try to move out of the way is likely blind.
In 2006, University of Florida scientists developed a gene therapy that helped restore sight to chicks with a certain genetic defect that were usually born blind. The genetic defect was associated with the Rhode Island Red chicken breed, that carry a defect preventing them from producing an enzyme essential for site. The condition is very similar to Leber congenital amaurosis type 1, or LCA1, a genetic defect in humans that causes blindness.