Economic factors affecting egg production : proceedings of the Tenth Poultry Science Symposium, 18th-20th September 1974 / edited by B. M. Freeman and K. N. Boorman.
Economic factors affecting egg production : proceedings of the Tenth Poultry Science Symposium, 18th-20th September 1974 / edited by B. M. Freeman and K. N. Boorman.