Enough eggs? One of the important issues for poultry farmers is the production rate-the percentage of days on which a given hen actually lays an egg. Ideally, that would be 100% (an egg every day), but realistically, hens tend to lay eggs on about 3 of every 4 days. ISA Babcock wants to advertise the production rate for the B300 Layer as a 95% confidence interval with a margin of error of How many hens must they collect data on?