Bill,
So you do feed the morning of the hunt? I figure as you, she needs the fuel for the day, but not so much it's a burden in her digestive tract while hunting. I cut the feed back about 30% the morning of the hunt and feed her up double that night. During the hunt day rests, I feed her some snacks (Milkbone or other bisquits). Water is in her bowl from the time I get out of the truck until we pack it up. I offer her water often, usually twice as often as I drink. I figure she's working harder than I. She'll drink from a bottle poured slowly and she ignores my offer when she's done drinking or not interested. Funny how fast she learned to drink that way in the dry fields I hunt.

Any recommendations on mid hunting day treats?