Check out my post in this thread.
https://www.backyardchickens.com/threads/is-my-chicken-ready-to-lay.1492293/#post-24890832
The technical definition is when they hit one year old. To me that's like saying a human is a legal adult at 16, 18, or 21 years of age, whichever age applies. It doesn't have anything to do with behaviors. From my observations a pullet starts acting like a hen around the time she starts to lay. In a mixed age flock that's when they stop running from the adults and are accepted into the pecking order.
Cockerels are harder. This can look different for each male. When they hit puberty the hormones often take over. The hormones tell them to dominate. They may fight other males for dominance, they may not. They mate with the pullets. At this age the mating act is more about dominance that fertilizing eggs that aren't being laid. The one on the bottom is accepting the dominance of the one on top, either willingly or by force (at least in that moment in time). At that stage it is almost always by force, the immature pullets don't want to be dominated by that hormone driven immature brat. As someone on here I really miss once said, watching pullets and cockerels go through puberty is not for the faint of heart. It can get pretty violent.
When the pullets mature into hens and the cockerels get control of their hormones the flock generally settles down into a pretty peaceful flock with the boys and girls acting like mature adults and each doing their part in the flock. It's getting through puberty that is hard. Occasionally you get a hen or rooster that refuses to grow up into a responsible adult but that is fairly rare. Still, it happens. You'll see several posters telling you to get rid of a cockerel acting like a hormonal driven cockerel where if you can get through puberty they will make a good flock master. Sometimes isolating that cockerel until he matures is one way to get through puberty. It's usually harder for you to watch than it is on the pullets.
I'll copy something I wrote about consenting adults mating. Immature pullets and cockerels are not consenting adults. Often even with mature adults it doesn't look this way. A rooster may not dance. A hen may run away instead of squatting. The rooster may let her go or he may chase her. As long as it ends with the hen squatting and no injury it is all good.
The rooster dances for a specific hen. He lowers one wing and sort of circles her. This signals his intent.
The hen squats. This gets her body onto the ground so the rooster’s weight goes into the ground through her entire body and not just her legs. That way she can support a much heavier rooster without hurting her joints.
The rooster hops on and grabs the back of her head. The head grab helps him get in the right position to hit the target and helps him to keep his balance, but its major purpose is to tell the hen to raise her tail out of the way to expose the target. A mating will not be successful if she does not raise her tail and expose the target. The head grab is necessary.
The rooster touches vents and hops off. This may be over in the blink of an eye or it may take a few seconds. But when this is over the rooster’s part is done.
The hen then stands up, fluffs up, and shakes. This fluffy shake gets the sperm into a special container inside the hen near where the egg starts its internal journey through her internal egg making factory.
He may be capable of fertilizing eggs but it's probably he is still a hormone-driven cockerel.
Scratch can be whole corn, cracked corn, or some mixture of foods. In the US it's usually a mixture of grains or seeds that are not ground. It's a little hard to talk about the nutritional value of scratch because it can be so many different things and mixes.
I don't know how you manage your chickens. Do they forage for much of their food or do they only eat what you provide? If they forage you've lost all ability to micromanage what they eat, they should get a good mixture. I suspect if you look around you will see plenty of flocks that the owners don't feed them anything, the chickens totally feed themselves as they have since there were chickens in your country.
My general advice if you are feeding all or most of what they eat is to try to feed different things. They do best on a balanced diet, if you only provide one thing may be missing certain nutrients. Try to feed things in moderation. Corn (maize to the British) doesn't scare me. Whole civilizations have thrived with corn as a basic food, but don't feed them exclusively corn. As best you can I'd give them various grains, fruits, vegetables, greens, grass, and creepy crawlies. Meat, fish, or shellfish has a lot of good things for them.
One problem with unground foods is that they will selectively choose what they prefer. So limit how much of that you offer. They are not going to starve to death, they will eventually eat what you provide if they get hungry. Some people manage their chickens, some people let their chickens manage them.
Yes. They don't sweat like we do but lose some heat by opening their mouth and sort of yawning. Heat is dangerous but as you say chickens have been in Santa Domingo for hundreds of years. They are not extinct there yet. Lots of water and shade is important. I water a shaded part of my run when it gets really hot, they like lying in that cooled ground. When it is that hot it doesn't stay wet long enough to cause health problems.
Not sure so I'll leave this to others.
