Spraddle Leg in Chicks: Symptoms, Causes and Treatment

Spraddle leg develops when the tendons and muscles that hold the legs beneath the body do not develop or anchor correctly during or immediately after hatching. The most common cause is preventable.

• Slippery brooder or incubator surface: The most frequent cause in backyard hatching. Chicks hatching on smooth surfaces (newspaper, bare incubator tray) cannot gain purchase with their feet, and the hips drift outward during the critical 24-hour post-hatch period when tendons are still soft.
• Incubation temperature errors: Overheating during the final days of incubation or sudden temperature fluctuations damage developing connective tissue and musculoskeletal structures in the embryo.
• Incubation humidity errors: Excessive humidity during the first 18 days prevents normal air cell development and can produce large, weak chicks that struggle to position correctly in the shell.
• Nutritional deficiency in the breeder flock: Vitamin B2 (riboflavin) and vitamin D3 deficiencies in breeding hens produce chicks with curled toe paralysis and leg weakness that mimics or accompanies spraddle leg. Ensure breeders receive a complete breeder ration.
• Genetics: Some breeds (particularly heavy breeds like Cornish Cross) have higher incidence of leg development problems. Chicks from closely inbred lines are also more susceptible.
• Traumatic hatching assistance: Chicks assisted too early from the egg (before the yolk sac is absorbed) are weak and more prone to leg deformity.

Spraddle leg is diagnosed visually at or within hours of hatch. Distinguish from other leg problems:

• Spraddle leg vs. curled toes: In spraddle leg, the legs splay at the hip. In curled toe paralysis (riboflavin deficiency), the toes curl inward and the chick walks on its knuckles while the legs remain in normal position.
• Spraddle leg vs. Marek's disease: Marek's leg paralysis typically appears at 4-16 weeks in a previously mobile bird, with one leg extended forward and one back. Spraddle leg is present at or immediately after hatch.
• Unilateral vs. bilateral: One affected leg is more treatable than two, but bilateral cases still respond well to early splinting.
• Assess alertness: A chick that is alert, vocalizing, and interested in food despite leg deformity has good prognosis. A lethargic, silent chick with multiple problems is less likely to survive.

Leg splinting (hobble brace) is the primary treatment and is highly effective when started within the first 24-48 hours of life.

Method: Cut a piece of medical foam tape, Vetrap, or fabric bandage approximately 1-1.5 cm wide and 5-7 cm long. Wrap gently around both legs just above the hock, leaving the legs positioned directly below the body at hip width. The brace should allow slight natural movement but prevent outward splaying. Replace every 24 hours and adjust as the chick grows.

Duration: Most mild cases correct fully within 24-48 hours. Moderate cases may need the brace for 3-5 days. Remove the brace once the chick can stand and take several steps without falling.

Supportive care: Place the chick in a small container with a non-slip surface (paper towel, rubber mat) so it can push up against the sides while the brace is in place. Bring food and water to the chick as it may not be able to reach them independently. Niacin supplementation (25 mg/gallon of water) supports leg muscle development during recovery.

• Line incubator hatching trays with non-slip shelf liner, rubber mesh, or paper towels with a rough texture. Never allow chicks to hatch on smooth plastic or metal surfaces.
• Set incubation temperature and humidity precisely and verify with a calibrated thermometer and hygrometer. Temperature spikes above 102 F during the first 18 days are the primary incubation cause of leg deformity.
• Feed breeding hens a complete breeder ration containing vitamin D3, riboflavin, and adequate calcium. Nutritional deficiencies in the hen transfer directly to the developing embryo.
• Do not assist chicks from the egg before pipping has been ongoing for at least 24 hours. Premature assistance produces weak chicks more prone to developmental leg problems.
• Cover brooder floors with textured paper towels for the first 2 weeks after chicks are moved from the incubator. Non-slip surfaces are essential during the period when tendons are still soft.