I don't see why not. It's just not as convenient as a single bag of feed.
Edited to add, following any fad diet isn't convenient either.
The optimal situation is to let the chickens decide for themselves what to eat, I think we both agree about this.
In order to achieve a balanced diet through their own choice, they need access to a sufficient variety of foodstuffs and from what I've seen, a lot of that is green vegetation, minerals, etc.
Such a range is difficult to supply in any supplied feed.
My view is they are a lot like us in the respect of diet, we/they can survive on a limited range of foodstuffs, but as we are constantly told by the nutritionists, and in some cases our parents, eat the greens!
So yes, a wholegrain plus, fermented diet if the basic nutrients provide a ball-court balance, is in my view better than a processed feed diet. But, having either as backup and all day on mixed vegetation is getting close to optimal.
I know I keep repeating this but it is absolutely crucial to good health; exercise. How the chicken feeds may be as important as what they eat for maximum health benefits. It's not just the physical health, it's the mental health as well. Many chicken I've known prefer ground feeding. Searching for and finding food I can imagine from how I feel about it, is enormously rewarding.
The what we feed debates including protein percentages, etc, are in my view blind alleys, no ration is ever going to maximize the chances of good health. The how, where, and when the chickens feed are what we should be looking at.