Possibly. On the other hand, it does makes sense to feed animals a diet to which they are evolutionarily adapted. Visit a zoo sometime and ask what each animal eats. They are all feed something intended to be nutritionally similar to their natural diet. Because that’s what works.
I tend to agree that, in many cases, more "natural" is more "healthy" but my main caveats would be:
1. "natural" does not automatically mean better. Depends on the context and many other factors.
2. Determining what is "natural" is also contextual based on what timeline you are talking about and what geographic location. To say "paleolithic ways of eating are healthier" is meaningless unless you think that we a. know exactly what they ate back then and b. every human had access to the same foods regardless of where they lives on the planet