My light brahmas have had scaly leg mites. I think it’s common with feathered feet so that will be something to watch. Because of their weight they might get bumble foot more than other breeds. Personality wise, the Brahmas are aloof but they always come running for treats
I don’t think DE does anything. After a bunch of fooling around with other products I have settled on Permethrin powder for lice and alcohol dips and Vaseline for scaly leg mites. (I forgot to mention they got lice from wild birds as well.)
For the floor, I’d go with something non-pokey. I use sand and haven’t had a bumble foot problem. I bought a year-old hen from a person with a rocky run and that Brahma had terrible bumble foot.