I'm an old timer but haven't had the opportunity to keep chickens for years on end. I have had my experiences in the past, though. I have chicken stories you probably wouldn't believe but all true.
This I learned with a flock of 200 laying hens, half White Rocks and half Black. Oh those black ones were beautiful. It just happened that when we started out with our babies, I didn't have a brooder set up so we built a little temporary pen in the back yard, with cardboard boxes and hanging light bulbs so they could cluster under the lights.
Every day, I spent time sitting on the ground, in their little pen and letting them crawl all over me. I realize now that just doing that, I created a bond between myself and them that produced something a lot more than just a bunch of laying hens. Later on, when they started laying, I helped them crow about it by showing off their eggs to the other 'ladies' and lavished the hen with praise. I even asked if 'I can have this'.
While this all sounds romantic, I also created a problem because not only did the girls lay bigger and bigger eggs, trying to outdo each other, they also didn't want anything to do with the henhouse. They wanted to lay those eggs on my lap, if they could. I found eggs in places, you'd never imagine, as they kept trying to give me their gifts.
These girls had the run of a whole farm, if they wanted, but they preferred to be near me and around the house. The closest thing to a fight breaking out was me trying to keep them off the porch swing. That's where they ALL wanted to take their afternoon nap. I was forever sitting on the porch swing, going through mail and doing a lot of writing and they would come, one at a time and perch on the back of it. When I stood up, they got dumped and had a fit. If I wasn't there, they still wanted that swing but it would only hold 3 before it tipped backward and dumped them all. There was always that 4th one that tried it and started a howl on the front porch. Problem was their poop and I was forever sweeping the porch and threatening their lives if they didn't stay off it. (oh that worked....yeah right)
I never had a sick bird, never saw a pecked back and never once witnessed an all out fight. Those were some happy, healthy birds and the only thing I can attribute it to was my attitude toward them. They were my children. I made sure they got their meds and kept the water fresh and clean. Feed happened in the morning when I let them out of the coop (I had them trained and they went in every night at dusk). Aside from the morning feeding, they got their meals on their own. Lots of bugs and leftovers from the table.
A neighbor, down the road, an old timer, dropped by one day to see the birds. He asked what breed they were and I told him and he said, "Ain't no way, those are Rocks. They're too big!" It seemed my girls were twice as big and fat as they should have been and boy did they lay those eggs.
Our yard was one noisy place with chickens running all over the place. If I happened to run to the store and back, they all chased the car and hovered around like puppies.
What did I learn from that experience? Happy chickens are healthy chickens.