Yes, that will do. Try the amount of a teaspoon every other day for the bully, at first mixed with her feed and after 3 days on a separate dish so she can avoid it if she has had enough.
Back then at first, my chicken went half crazy for the real butter, but after a few days they hardly picked...
1) Switching the feed to All Flock Raiser I would abstain from feeding mealworms or shrimps etc.
2) I would keep the bully separated and feed her the new mix plus butter for at least a week before trying to release her again. These feed changes need some time to take effect on her.
But I would...
And if you want to completely switch to the All Flock Raiser (20% crude protein) like @aart does with her flock successfully, you might just feed them some raw carrots and other vegetables and fruit as treats so their kidneys will not be compromised by the higher protein percentage.
Any time you change the feed do it slowly over a period of at least 7-10 days just adding a bit more of the new feed to the usual each day until it is 50% from each. And observe how they do with the new mix.
By doing so you will be able to adjust the feed to their actual needs by just switching...
Yes, here it is allowed again after some scandals in the past. But it will be added fish/seafood clippings or else. And the chicken industry processes and feeds their own worn-out layers back to the newer ones.
But I don't feed it. ;)
My chicken get additional dairy produce, venison/game etc.
I would cut the corn completely as this only deletes the protein percentage even more.
And of course, just like before mentioned the run should be extended so they will be able to not invade each others personal space when passing by.
Is there a complete list of ingredients somewhere?
16% crude protein might not be enough if it consists of only herbal proteins. The total amount of 16% crude protein does not mean 16% digestible protein. A hen that is not free-ranging and therefore not able to feed herself the necessary animal...