Hi neighbor. They will be fine with all of them eating either All-Flock or Starter. If you look at the tag you’ll see the list of nutrients is basically the same. I don’t know if you are feeding medicated Starter, I don’t but many people do, but I would be hesitant to feed medicated feed to laying hens. Some people do though. By the time you integrate them they will probably be on Grower anyway.
There is a difference of opinion on here as to whether feeding a rooster Layer causes problems due to the excess calcium. Some people worry about it, some don’t. The excess calcium thing is not about what is in one bite, it’s about how much in total they eat each day, and that over a time period. A rooster does not eat as much as a hen that is laying an egg and replacing 1% to 2% of her body weight every time she lays an egg. If they forage for part of their food or eat a lot of low-calcium food like many treats they are not going to get as much calcium as a rooster eating nothing but Layer. I never feed Layer, always Grower or Starter with oyster shell on the side but I practically always have younger chicks in my flock.
Your older chickens will be fine in the weather. I’ve had chicks less than 6 weeks old go through nights where the lows were in the mid-20’s. Once they are feathered out they handle the cold really well. Our heat in the summer is much more of a danger than out cold. The younger chicks need heat until they feather out. The age they feather out depends on a few things. If they eat a higher protein feed, they will feather out a little faster. If they are exposed to the cold, they feather out faster. I don’t raise any exotic chickens, just the standard dual-purpose, so I can’t speak for breed maybe making a difference.
Personally I don’t like a hen that lays a double yolked egg regularly. That does not suit my goals. The eggs don’t fit in a carton, you can’t hatch them with a realistic chance of success, and they don’t fit in recipes. They do scramble or fry up well. Occasionally is not a big deal, but regular means something is wrong with her internal egg making factory. She is releasing more yolks at a time than she should. Don’t let this freak you out, most hens can handle the double yolked eggs fine, but by laying the larger eggs she has a greater chance of having problems laying, like prolapse or maybe internal laying. Many people would love to have that hen but she just doesn’t fit my personal goals.
You may have noticed I don’t give a lot of hard and fast rules. A lot of this stuff is personal preference. We’ve all got different goals and situations. Chickens are pretty tough and adaptable. If you can provide the basics, food, water, protection from predators, and some protection from the environment they will do fine.
