Chickens can get ear infections which are referred to medically as otitis interna and externa. Although not outwardly apparent, chickens have ears that on each side of their head, which are located just below and behind their eyes. The color of a hen's earlobe is actually indicative of the color of eggs that she lays. Chickens with white earlobes tend to lay white eggs and chickens with red earlobes lay colored eggs--usually brown, but also greenish or blue for certain breeds.
There are three chambers which make up a chicken's ear, consisting of an outer, middle, and inner chamber. An eardrum separates the air-filled outer and middle chambers from the inner ear potion, which is filled with fluid. Ear infections can affect any one or more of these chambers.
- Inner ear infections: The chicken's inner ear is considered to be a part of their nervous system, and helps the chicken with balance. This is why inner ear infections can cause neurological signs in affected chickens, in the form of head tilt, loss of coordination and balance, and torticollis (wry neck). Inner ear infections are most likely caused by a viral infection, and are much more difficult to treat.
- Middle ear infections: Middle ear infections are most likely caused by a chronic bacterial infection or tumor. Bacteria most commonly isolated include: Enterococcus faecalis, Escherichia coli, Pasteurella multocida, and Pseudomonas aeuroginosa. Bacteria can sometimes enter the chicken's ear through a small opening in the roof of the mouth, referred to as the infundibular cleft. The infundibular cleft opens directly into the chicken's auditory canals of the ears. The chicken's ears are inside their head, covered by a tiny clump of stiff feathers. Just behind the feathers sits the chicken's earlobe. These infections tend to be a little trickier to treat, as many of the invading organisms are considered to be opportunistic and highly resistant to many antibiotics. Thus, its often best to conduct antibiotic sensitivity testing prior to starting the bird on any treatment, in order to select the most effective antibiotic against the invading organism.
- Outer ear infections: Infection to the chicken's outer ear is usually caused by common bacteria or fungi. These types of ear infections are generally considered to be relatively simple and straightforward to treat.