Urgh. That “partially formed” strawman again - although to call it a strawman may actually give it too much credit considering how nebulous what the hell they understand by it is.
Simple filaments (like we see with pterosaurs as well as with all those other mammals who don’t have heavily reduced fur like us) can go a long way towards providing thermal insulation. Indeed, even modern birds have a kind of “partially formed” feathers, downs, that serve exactly this function. Flight feathers only appear much later over the course of an evolutionary process of tens of millions of years.
The needed macromutation with hundreds of properly sequenced base pairs would be as hyper-improbable as the chance formation of the protein we discussed above.
Even if your claims were correct, unlikely things happen. Also, perhaps humanity was not the first technological species to evolve on Earth to evolve and feathers are the result of ancient genetic manipulation. It could even be aliens. Any naturalistic explanation, no matter how improbable and far-fetched, is still infinitely more plausible than absurd and thoroughly falsified creationism.
We can confidently say that virtually all steps in the alleged macroevolution process would fail the UPM test.
I am an actual biologist, yet I have never heard of such a test.
Evolution is falsified.
Even if evolution could not explain the specific phenomenon of feathers, it would not change the general observations that, over the course of the world’s history, life on Earth has changed, that it continues to change through the mechanisms of mutation, selection and gene drift, and that all life forms without exception show a nestled hierarchies of similarities from which universal common descent is an inevitable conclusion. Indeed, above, I gave some explanations that would allow feathers to be of non-evolutionary origin that would still be completely consistent with evolution.