You guys probably know this, but one of the best ways to tell if a deer is healthy or not is the appearance of its coat.
Healthy deer groom themselves and their coat is slick and shiny. Unhealthy deer often have ragged coats, poor hair quality, and general lack of grooming, even before wt loss occurs.
A good example... we have a 3.5yo 8 pt that was the best buck we have on one of our farms. We passed him, but neighbors blew off the bottom 1/3 of his back left leg. He came out limping in front of me just before Thanksgiving. He fed, and even chased a doe around a bit. Seemed fine, but I knew the new few weeks would tell the tale.
When I came back up for second rut in December, I was planning to put my daughter on that deer and take him. I checked trail cams and had pics of him as recently as the day before, and he looked healthy, only minimal wt loss, and his coat was slick and shiny. I knew he was going to make it just fine, so we left him and hunted elsewhere.