What kind of chickens are you raising? What are your goals for the flock? Since you have 4 month olds I am pretty sure those are not the Cornish X meat birds but I hate to guess. Are they to be an egg-laying flock, show birds, or just pets? Will you be eating them or the males? Do they forage for a lot of their food? Do you give them a lot of treats? If so, what treats?
What are the percent proteins in those feeds? That information should be on the label. As long as the calcium levels are closer to 1% than 4% the percent protein is the most important information on the feed label.
We all feed out chicks differently. A lot of that depends on your goals for the flock. I don’t want big chickens for several different reasons. For others having big chickens is a priority. I normally start my chicks off with a 20% protein Starter for the first month or so but then switch to a 15% Developer/Finisher. They forage for a lot of what they eat. Many people on here will be horrified the way I feed my chickens but it works well for me, my flock meets my goals.
You have a lot of latitude in how you can feed your chickens and have a healthy flock, but your goals have a lot to do with how you need to feed them. I just don’t know enough about your goals or those specific feeds to be able to be very specific with your situation.
