Offer free-choice oyster shell for extra calcium

Provide crushed oyster shell in a separate dish so laying ducks can self-regulate their calcium intake. Duck eggs have thicker shells than chicken eggs and require more calcium per egg — roughly 5–6 grams compared to 4–5 grams for chickens. Layer feed alone may not supply enough calcium for high-producing ducks, especially breeds like Khaki Campbells laying 300+ eggs per year.

Why It Works

Insufficient calcium leads to thin, soft, or shell-less eggs and eventually causes the duck to stop laying entirely as her body protects against skeletal calcium depletion. Free-choice oyster shell lets each bird consume exactly the calcium she needs — heavy layers eat more, non-layers eat less. Oyster shell dissolves slowly in the gizzard, providing a steady calcium release during the overnight hours when shell formation occurs.

Tips

• Keep oyster shell in a separate container, never mixed into the feed
• Start offering when ducks reach laying age (5–7 months)
• A 5-pound bag costs $10–15 and lasts a small flock several months
• Crushed eggshells can supplement but should be baked at 250°F for 10 minutes first to prevent egg-eating behavior