In a planned production program, Iowa poultrymen need to consider both the time of year their eggs are produced and the quality grade. That's because both factors have a large influence on income from egg sales.
Eggleton, Leonard Z.
"Planned Egg Production and Quality,"
Iowa Farm Science: Vol. 5
, Article 5.
Available at: https://lib.dr.iastate.edu/farmscience/vol5/iss11/5