Making our own food, how much of each ingredient should we add for a balanced diet?

[nuthatched]

but if you let them free range they will be even healthier if given the food forest type living conditions.

The truth of your statement is that local environment in the key component. Very few regions can support a modern dual purpose flock, let alone keep them in great condition. Mine can't. Especially in the 'dead seasons' that don't start with S.
If you live were the climate is temperate, it could work but I'd recommend more game fowl type for this practice.