Penguin-Like Squat Posture in Hens

Correct Answer: Vitamin D3

Vitamin D3 (Cholecalciferol) deficiency in hens causes the characteristic 'penguin-like squat' posture due to severe bone demineralisation and softening of bones, making the bird unable to maintain normal posture.

Vitamin D3 Deficiency Diseases by Species

• Children: Rickets (soft, deformed bones — bow legs, rachitic rosary)
• Adults: Osteomalacia (softening of bones)
• Hens: Penguin-like squat posture, soft-shelled eggs, reduced egg production

Vitamin D Metabolism

Vitamin D acts as a hormone. It is synthesised in the skin on exposure to sunlight (UV radiation converts 7-dehydrocholesterol → Vitamin D3). Its precursor is cholesterol. It promotes calcium absorption through the GIT.

Why Hay is Rich in Vitamin D

Sun-drying of forage during hay-making causes conversion of ergosterol to Vitamin D2 — so hay is an excellent source of Vitamin D.