Gastrocnemius Tendon Rupture in Turkeys: Why a Turkey Sits on Its Hocks

Gastrocnemius tendon rupture is a tear of one of the major tendons at the back of the lower leg, just above the hock. When this structure fails, the turkey loses normal support of the hock and may become suddenly lame or sit back on the hocks instead of standing normally.

In poultry, this problem is described most often in meat-type chickens and only rarely in turkeys. Even so, it matters because a turkey that is down on its hocks is at risk for pain, pressure injury, dehydration, and difficulty reaching feed and water. In some birds, one leg is affected first and the opposite leg is then overloaded.

This injury may happen after the tendon has already been weakened by inflammation of the tendon sheath, especially reoviral or staphylococcal tenosynovitis. It can also appear to happen spontaneously in heavy, fast-growing birds when normal body weight or sudden movement exceeds what the damaged tendon can handle.

For pet parents, the key takeaway is that this is not a minor limp. A turkey sitting on its hocks needs prompt veterinary attention to confirm the cause, protect welfare, and discuss realistic care options.

In poultry, gastrocnemius tendon rupture usually happens when force is applied to a tendon that is already weakened. Merck Veterinary Manual notes that rupture commonly follows infectious tendinitis or tenosynovitis, especially from avian reovirus or staphylococcal infection. These conditions can make the tendon thicker but mechanically weaker, so it tears more easily.

Body size and growth rate also matter. Heavy birds place more stress on the hock and tendon structures, and a sudden jump, awkward landing, breeding activity, rough handling, or slipping on poor footing may be enough to cause a partial or complete tear. Once one leg is injured, the other leg may be overloaded, which can lead to bilateral problems.

Environmental and management factors can add risk. Crowding, slick flooring, poor litter quality, limited traction, and delayed treatment of earlier lameness all increase strain on the legs. In flock settings, your vet may also think about infectious synovitis or other tendon and joint diseases that can weaken tissues before rupture occurs.

Because several conditions can cause a turkey to sit low or become lame, the visible injury is only part of the story. Your vet may recommend looking for the underlying reason the tendon failed, not only the tear itself.

Diagnosis starts with a hands-on exam and a careful history. Your vet will ask when the lameness started, whether it was sudden or gradual, whether other birds are affected, and whether there has been recent trauma, slipping, fighting, breeding pressure, or signs of flock disease.

On exam, your vet may find marked lameness, a dropped hock posture, swelling, hemorrhage, or a firm mass on the back of the leg above the hock. In poultry, a ruptured gastrocnemius tendon can sometimes be palpated as a hard mass in this area. The exam also helps rule out fractures, hip or stifle injury, bumblefoot, neurologic disease, and generalized weakness.

Radiographs may be recommended to look for fractures or other skeletal problems, especially if the bird is valuable as a pet, breeder, or exhibition turkey. If infection is suspected, your vet may discuss flock diagnostics such as necropsy of affected birds, sampling of tendon or joint tissue, bacterial culture, or PCR testing for agents linked with tenosynovitis, including avian reovirus or Mycoplasma synoviae.

In many backyard cases, diagnosis is a combination of posture, palpation findings, and exclusion of other causes. If the bird has been down for a while, your vet will also assess hydration, body condition, skin injury, and overall welfare before helping you choose the most appropriate care plan.

Prevention focuses on reducing tendon stress and catching earlier leg disease before a rupture happens. Good footing matters. Keep litter dry, avoid slick surfaces, and make sure birds can move without repeated slipping, piling, or awkward jumping. Heavy birds need easy access to feed and water so they do not have to compete or scramble.

Flock health also matters. Because tendon rupture can follow infectious tenosynovitis, work with your vet on biosecurity, sourcing poults from reputable disease-controlled breeding programs, and investigating any flock pattern of swollen hocks, lameness, or poor mobility. Merck notes that control programs for Mycoplasma synoviae in US turkey breeders have reduced infection pressure, and good biosecurity remains important.

Management should support steady growth and safe movement. Avoid overcrowding, reduce rough handling, and separate aggressive or overly active birds if breeding pressure or fighting is causing injuries. Prompt evaluation of any lame turkey may help identify tendon or joint disease before a complete rupture occurs.

Not every case is preventable, especially in fast-growing birds, but thoughtful housing, traction, flock monitoring, and early veterinary input can lower risk and improve welfare.