I can definitely see both sides on this one. On the one hand I know exactly what you mean Kate with regards to people stepping in too much thinking they are "helping" when really they should let things progress naturally.
Helping chicks to hatch is one example that came to my mind...if the conditions are right you should never need to help. If they are not strong enough to get out on their own then really it says something is wrong to begin with. The odds of a wise hen caring for a chick like this if it is assisted in hatching is slim to none, so then we as humans want to try to save and take it even a step further by hand feeding..... In reality, the wisest thing to do is simply let things progress as they naturally would and try to raise strong, healthy birds that will raise the next generations.
We as humans nuture weakness because of pity, while the logic of most animals tells them to avoid it like the plague as it is the wise thing to do. This is one important aspect of a ethical breeder that is often overlooked for sure. It is hard to accept, but se simply can not expect them to all survive, and if we really care about the species as a whole sometimes tough decisions need to be made
On the other hand though you have those who in reality are completely foolish when it comes to breeding, which is what the OP seems to be in my opinion. Survival of the fittest is only appropriate when he birds are given a good chance to begin with, otherwise there are just countless deaths waiting to happen.
What kind of yolk can a hen produce when she is eating basically only seed and cuttlebone? In turn, how strong will that chick be when it hatches, and what kind of crop milk could she possible give it? As they grow on such a poor diet, it is only logical that the smallest and weakest will suffer and die first because their little bodies have literally been starved of much needed nutrients even before they even hatched.
Is this survival of the fittest to me? No. This is the killing of helpless chicks because of the owners blatant stupidity whether they want to admit it or not. Failure to do the most basic of basic research, and denying the birds even a basic breeding diet that they and their chicks desperately need, is something there is no excuse for in my book. There is always a way to get the needed information if people want to do so, it is just a matter if if they have any desire to learn what is required.