The theory is entirely accurate. All you have to do is look at the Monarch Butterfly. It's caterpillar ONLY eats milkweed. This is, in my opinion, one of the many reasons they are failing to thrive on modern day earth. They are a flawed species, which is why they are doing so poorly in our current situation (I am not saying we should just keep on polluting the earth and let the Monarchs go, but they just aren't a resilient species at all and such creatures do not last.)
Now look at the Eastern Black Swallowtail Butterfly. It is thriving incredibly well. Why? Because it is the fittest. It has a ton of host plants, the caterpillars are much more resilient than Monarch caterpillars, and they don't go through the risky escapade to Mexico. They are a bouncier, hardier species than Monarchs and as such are surviving excellently.
Now we turn our attention to chickens. Chickens have eyes a lot like ours, with an exception in that they can detect ultraviolet light. One of the ways they use this ability is to observe the feathers of their young. Shiny feathers mean healthy chicks, dull feathers mean unhealthy chicks. After this conclusion, the mother hen will prioritize the healthier chicks, making sure they get more food. She is performing by instinct natural selection, ensuring only the cream of the crop passes on her genes.
Another interesting thing about chickens is that if a member of the flock shows any signs of illness the rest of the flock will either starve, distance themselves from, or execute the affected flock member in order to ensure the flock maintains a healthy, thriving order. This goes for birth defects as well. A mother hen will not stand for a sickly chick. She will most often kill it so she can better prioritize her healthier young.
Humans break the rules of natural selection. We are compassionate, we are incredibly intelligent. For a species as a whole, we are resilient. How we will hold up over time, it's hard to say. But that's a different topic. The current topic involves natural selection within a species.
So let's talk a bit about birth defects and parental bonding. In our society, good mothers make sure all of her children are treated equally and all have the same chance of survival. These are morals that we as an intelligent, independently-thinking, caring species have invented. Natural selection is always in effect, a child born with perfect eyesight under the same conditions as a child born blind will almost always thrive better. For blind chicks, being born is the end of the road. The hen will execute or ignore them. What makes humans so unique is that we will care for our young, therefore interfering with how natural selection was meant to function. But, we don't really rely on natural selection the way other species do, do we? Because of our position as the (questionably) dominant species of earth, we don't require rigorous enforcement of natural selection. We have the option.
Darwinism has only been misinterpreted by people who don't quite understand how it works or don't want to understand how it works. As a theory, it is excellent. All you have to remember is how different we are as a species from other animals on this earth, and the theory is really easy to accept.
