Roosters are only needed for the obvious
I do not personally deal with chickens and eggs but Tristans parents breed/raise/sell chickens/ducks and eggs and i am there quite alot. Not on a huge scale but around breeding season. They keep alot on their property as well as layers and pets. Hes asleep atm but i can give you some info.
The laying period starts when the hen is about 18-20 weeks old. The older the hen, the bigger the egg. The colour also depends on the breed. Productivity diminishes after the first year. It is still good the second year, but then declines rapidly. At about three or four years, production is not very efficient. They generally lay one egg per day, and that gets later and later in the day, if it is too late, they have a days rest so they may only lay 2 eggs per three days.
Eggs are different shades of blue, white and brown. They can be dull or shiny. Here is an information chart with chicken breeds, egg colours/shades and pics included, as there are alot to list.http://www.ithaca.edu/staff/jhenderson/chooks/dual.html
In spite of their high cholesterol content, chicken eggs offer several healthy benefits. Consider the following:
* Eggs are one of the best sources of protein, vitamins, and minerals. The protein found in eggs is of a higher quality than the protein found in meat and fish.
* Eggs are low in calories: one large egg has only about 75 calories.
* The high protein white averages only about 17 calories and has no fat or cholesterol, making it an excellent diet food.
* There are nutrients in eggs that are beneficial in preventing macular degeneration, which is the leading cause of blindness in the elderly.
* Eggs are rich in choline, which is helpful in fetal brain development. Choline levels in women drop during pregnancy, so it may be beneficial for women to consume eggs during pregnancy.
I know you said you wanted people who worked directly, but you also said you needed information, so i hope this helps.