Perosis is a chicken health condition. Perosis causes severe lameness and deformity in growing birds. While not immediately fatal, affected birds suffer and cannot walk or feed normally. Prevention through proper nutrition is far superior to treatment. This guide covers what to watch for, causes, treatment, and prevention strategies.
What It Looks Like
Watch for these signs:
Legs: Bird cannot stand or walks with severe difficulty; drags back legs
Knee/hock joint: Leg bones appear bent or deformed; joint looks twisted or pushed to the side
Hock and knee joints: Joints appear larger than normal, puffy, or inflamed
Overall development: Young birds grow slowly and remain smaller than healthy peers
Nervous system and legs: Bird staggers or loses balance; hind legs may be paralyzed
Feathers: Feathers appear thin, rough, or unkempt
Likely Causes
- Manganese deficiency in diet (essential for bone cartilage formation)
- Choline deficiency (related metabolic disorder)
- Poor quality or imbalanced feed
- Lack of mineral premix in home-formulated feed
- Young growing birds most susceptible (critical development period)
- Genetic predisposition in some lines
About This Condition
Body System Affected: Musculoskeletal system (bones and connective tissue)
Severity: moderate
Contagious: No, not contagious
Affected Age Groups: chicks, pullets
What to Do
Switch immediately to commercial poultry feed meeting NRC standards for manganese (50-the appropriate amount/kg for growing birds). If formulating your own feed, include a complete mineral premix. Recovery is slow once deformity occurs; prevention is far more effective. Severely affected birds may require euthanasia.
When to See a Vet
See a vet if your chicks show lameness, leg deformities, or poor growth. Your vet can evaluate the feed and recommend adjustments.
Prevention
Use high-quality commercial feed meeting NRC nutrient standards. If mixing your own feed, include a complete mineral/vitamin premix. Ensure adequate manganese (50-the appropriate amount/kg). Store feed properly to prevent degradation. Use fresh feed.
Frequently Asked Questions
Q1: Is perosis permanent?
Once bone deformity occurs, it is permanent. Prevention through proper nutrition during critical growth periods is essential. Early dietary correction may prevent further deformity but does not reverse existing damage.
Q2: What is the difference between perosis and slipped tendon?
Perosis is a metabolic bone disease from manganese deficiency. Slipped tendon can result from perosis but is sometimes classified separately. Both involve bone/joint deformity.
Q3: How common is perosis today?
Rare in flocks fed commercial feed. It occurs mainly with poor-quality feedstuffs or improperly formulated home-mixed feed. Prevention is simple with proper nutrition.