What you have been feeding will cause a lot of fat on a chicken which can lead to liver (fatty liver syndrome) and egg laying issues.It's probably 14% protein with recognizable corn bits. A friend gave me 50# hulled sunflower seeds and 50# shelled peanuts,
Sunflower seeds and peanuts will be a nice extra to give during cold winter temperatures, but are totally ovee the top in summer time when they will be able to forage for insects and worms.
The feed from your local mill seems to contain too much corn which is also known to fatten up instead of providing necessary protein as field peas do.