Seriously, Jim,
A hen will only lay about 500 eggs in its lifetime. After that point, they are considered "spent" hens. They typically come into lay at about 20 weeks of age. Normally, a hen lays an egg about every 28 hours, on average. In practice, hens lay in the early morning hours, so a given hen will typically lay 6 eggs every week, skipping one day a week.
Some people "molt" hens by withholding feed until they stop laying, giving them a chance to rebuild bodily resources. But, in a backyard situation, it's tough to molt them, because you can't really cut them off from nutrition completely, and they will resort to cannibalism if they get desperate. I just let them lay continuously until they're spent.
Once hens get near the end of their laying phase, they can begin to lay abnormal eggs - thin albumen, thin shells, deformed shells. That's them, telling you it's time to 'take them to town'.
We used to get day-old chicks every other year and then raise them up in a brooder until they were "pullets", 12-18 weeks of age. That's when they would go into the coop. But, that can be a hassle if you don't have barn space for the brooder, because, with shavings for bedding, it's VERY dusty in the house or garage. Any more, I'm very satisfied to pay about $7 each for fully developed pullets, which will start laying soon after you get them. Thus, I'm skipping the entire brooder phase. The other thing is that commercial pullets are debeaked, which completely eliminates the cannibalism problem. After impacted crop, cannibalism is the greatest killer of backyard hens (presuming you can exclude the coyotes and foxes).
We also used to play around with heritage breeds, but many of these don't play well together when mixed. Anymore, we go for a good hybrid "red sexlink" breed (they've been genetically engineered so that if they're red, they're females). They lay brown eggs and are very robust and congenial with other chickens or humans.
I run my coop "all-in, all-out". That means, I have some downtime between groups to give me time to do repairs, and most importantly, clean and disinfect. If you put a 'break' in flow like that, you eliminate issues with most infectious diseases. It is a Bad Idea to put new pullets in with old hens. Clean thoroughly with soap and water using a brush or powerwasher, and then use a good disinfectant, like phenol (Tek-Trol or One-Stroke Environ).
We feed our hens all sorts of table scraps, and you can spoil them with treats. Avoid things like carrot ends which they can choke on. Once, I had a hen die right before my eyes, choking on a carrot end. Their favorite treat is sweet corn cobs. Watermelon rinds is a close second. They love stale bread, just crumble it up in small enough pieces so they won't choke on it. Stale corn chips and popcorn are also favorites. They'll yell at me for treats if they see me out in the yard!
-Paul
