Introduction

A condition of chickens, turkeys and ducks seen worldwide and due to Vitamin D or calcium deficiency. Predisposing factors include small body size, high production.

Signs

• Lameness.
• Soft bones and beak.
• Birds go off legs.
• Drop in production.
• Soft-shelled eggs.
• Enlarged hocks.
• Birds rest squatting.

Post-mortem lesions

• Bones soft and rubbery.
• Epiphyses of long bones enlarged.
• Beading and fracture of ribs.
• Beak soft.
• Parathyroids enlarged.

Diagnosis

History, signs, lesions, bone ash. Differentiate from Marek's disease, spondylitis.

Treatment

Over-correct ration vitamin D, calcium carbonate capsules, place on litter.

Prevention

Supplementation of vitamin D, proper Ca and P levels and ratio, antioxidants. As birds progressively mobilise skeletal calcium for egg production through lay, skeletal size and mineral content at point of lay are critical.