A half mile is 880 yards or almost 9 football fields. Seems excessive for most Brittany bird dogs.
My dogs adapt pretty well to the cover and conditions (weather). Normal range is about 25 yards - 100 yards ... with most of the time spent about 60 - 75 yards out ... the coverage is pretty extensive left and right too ... not just out in front. They all have figured out how to pin runners too ... not always, but often enough to help fill the bag.
In short grass prairie, they may stretch out quite a bit pushing towards 150-200 yards but that is the exception.
All my Brittanys have set these ranges mostly on their own. I may work with them a bit on range, but I have now trained my 6 Britts on my own and do not use electric collars in training or hunting. Same for my brother's dogs.
My one Britt that ran far "bigger" than the rest will be approaching 14 years of age this fall. She still tries to run big, but her breathing can't keep up ... so she is mostly retired with a few 20-minute hunts in spots I know are compact and holding birds.