Gosh they are pretty
Only switch to layer once they are laying, and even then, layer is often just minimum protein (it assumes 100% of their diet is the feed) so you can feed them a little of the higher protein as a mash or a treat (this is nice if you have another who eats that type and you want to finish a bag or just get through the BIG bag while it is fresh. I had just one Tom, so he took a while to eat a 25kg/50lb bag, the chickens helped me have a reasonable turn over in bags)
Just make sure there is free access calcium on hand.
Take a look at the labels of both your Turkey food and the starter, likely the only difference is a small amount of protein, which is fine either way since they eat lots of fresh foods in your garden. Pick the one that you can find most often and has a good price. As much as chickens love treats, for some reason they like consistency in their daily food... They dislike when you start a new brand
If I have to switch brand or type, they will go on hunger strike on me. But if they get a treat of something off the supper table, they climb over each other to get at it. I don't get it... But since they are females, sometimes best to just understand that I don't need to understand, just respect it.