“Spondylolisthesis!!” It’s easier to say Kinky Back.

From Newcastle to Mareks, dermatitis to LT, there are a number of diseases or challenges that can affect poultry-- that is no secret. Kinky Back seems to be one that everyone has a harder time understanding and we can see why. Everyone has their own way of explaining exactly what this disease is. Spondylolisthesis is the technical name and humans can actually suffer from it as well. This is a condition of the spine where one of the vertebrae moves more than it should and slips out of place. 

In birds, however, there are two forms of Kinky Back-- both of which cause swelling and compression of the sixth thoracic vertebra. This specific vertebra is extremely important for motor function as it is the only one not fused to a neighboring vertebrae and able to move freely. Swelling at this junction in extreme cases causes posterior paralysis and even death. 

The first form of Kinky Back is a noninfectious, metabolic disorder which is aggravated by fast body development. Think extreme growing pains. Due to the pain, you might find birds sitting on their hock or rump with their legs outstretched, using their wings to walk, or even walking backwards. In its most severe stage, Kinky Back will cause birds to lie on their side until dying from dehydration. 

Since this form of Kinky Back is related to the birds’ genetic predisposition for rapid growth, there is little to be done outside of limiting their feed availability. There is however, a second form of Kinky Back we do have more control over. 


Caused by Enterococcus ceccorum, an intestinal bacteria needed for proper digestion, bacterial Spondylolisthesis occurs when bacteria in the gut migrate to the free thoracic vertebrae. Once there, the bacteria cause uncontrollable infection resulting in compression of the spinal column and eventual paralysis. 

This is most common from weeks 4 to 6 since Enterococcus are not present in the intestinal tract until week 3. But, how does this actually happen? What are intestinal bacteria doing in the bird’s spine? It is actually really simple and most often comes down to stress- like everything else. 

When a bird experiences things like heat or cold stress, their cells begin to talk to each other- chemically speaking. In the intestine, this causes junctions between cells to open just enough to allow bacteria to leave the gut and travel to other places. In the case of Kinky Back, they are headed to the spine. Once there, swelling is caused by buildup of fluid attempting to mitigate bacteria. Unfortunately, this usually damages the bone and causes an abscess. 

With mortality rates averaging 5-15% and morbidity ranging from 20-30%, it is imperative to take preventative measures. Everything starts with eliminating stressors and improving gut health. Paying attention to environmental stress factors will ensure that your birds have a quiet and calm start to their grow-out. This will decrease the likelihood of bacterial migration. Improving gut health means promoting beneficial microbiology while eliminating the harmful. This can be accomplished using probiotics such as our Big Ole Bird. 

To put it simply, the same way to prevent issues in our own body works on your birds too! Good nutrition and healthy bacteria make a world of difference in the early stages of a grow out! To help with structural issues, make sure your birds are getting a good nutritional foundation those first 10 days. If you want to prepare for a bacterial challenge, make sure the birds microbiome, bacteria and their environment, are a healthy and thriving system ready to take on any challenge. 


As always, if you have any questions, give us a call. You can reach Allen at 800-608-3755 or [email protected] .

The Author
Allen Reynolds
Poultry Development
Allen has worked in the poultry industry for 15 years, gaining experience in raising birds, house operations, equipment and bird health. As our Poultry Development Rep, he is passionate about improving the lives of farmers through natural poultry solutions and education. In addition to outstanding customer service and superior poultry support, he is also involved in helping growers through our Poultry Biosecurity Youtube Channel. Allen works to stay up to date on the latest industry news to bring relevant topics to our subscribers. He is often seen as the host, sharing profitable tips and tricks to poultry farmers. Outside of the office, Allen enjoys working on the farm, scuba diving, and riding dirt bikes.