I find this very odd, as beef cattle in Australia generally run wild until they are mustered, yarded up and then trucked / put into different paddocks,
Working on a station myself, I'm not sure how a drone would really go unnoticed and, more importantly, how it would actually be of any use.
The only time I could see it being useful is during large-scale sales, but realistically you could just walk around and observe on the ground!
Btw, this drone thing has PETA written all over it!