The a above ranch is 18,000 acres. That is 28 square miles. Hardly shooting fish in a barrel. Now that said - even animals in unfenced ground can lose some of their natural wildness depending on the management of the habitat they live in - extensive predator control, year round feeding, daily extent of human activity, etc. The deer on my place, where I am out and about everyday, are much calmer than they are on the neighbor’s high fence 1400 acres - where there is only intermittent human activity. If I didnt mind doing it, I could shoot a deer off my ranger many days within ten minutes of leaving the house. I have rode around on neighbor’s high fence area several times and maybe once have seen a deer you could shoot - all the rest were white tails going through the woods. I have never hunted a high fence area - but neighbor’s deer are much “wilder” than my deer.
That said, I have no idea about the inherent “wildness” of those Texas Dall’s. But, If I was of a mind to do it, and the fee was not a problem - I would sure not let the opinions of others sway me one little bit.