With regard to footwear and headcover, a monk is allowed to wear sandals which do not cover the toes or heels, and to cover his head with a cloth (like a fold of his robe, or his sitting cloth), inside the monastery or in uninhabited areas, like a forest, or if he is unwell. So if, for example, it's blazing hot and he'd burn his feet walking on hot pavement, then it would be allowable to wear sandals even in town. Hats, caps, and also turbans are out. It is my understanding that wearing shirts, thermal underwear, etc. is technically not allowable. It is allowable to wear thick robes though, and to wear a cloak made of woolen felt called a pavara or pavurana. Monks in the West, however, prefer to wear tropical attire in accordance with SE Asian tradition, and then wear shirts, etc. underneath. I must admit that wearing a felt blanket in cold weather makes it difficult to accomplish useful work. But monk robes aren't really designed for work either.
And it really is not allowable for a monk to order, or even hint, to have an animal killed. And if a monk even suspects that an animal was killed for his sake, he is forbidden to eat its flesh.