Which three items are non-negotiable additions beyond the primary feed for a Wyandotte flock?

Water, grit, and oyster shells (for layers).

While a high-quality, age-appropriate commercial ration forms the foundation of the Wyandotte diet, there are three supplementary elements that must always be provided to ensure comprehensive health and production. First is constant access to fresh, clean water, essential because dehydration severely impairs feed utilization and egg output. Second is grit, necessary for physical digestion in the absence of teeth. Third, for any hen in production—which Wyandottes often are, even through winter—free-choice access to oyster shell is mandatory to supply the high levels of calcium needed for strong eggshells.