Sore feet or sore muscles/joints?
Hard to say - it was pretty hot the last day (80s) so I think it was just the exhaustion. Footing was very good and no stubble so I think his feet were ok. He just looked whipped. Walking behind us - ha ha.
We mostly kept him in the shade of a tree and well watered. At the very end he had no interest in "find the bird" - which I've never seen him lose interest in. We knew then he was toast.
Got back home from out west late last night and he was playing with his toys and frollicking like a pup so I guess no serious issues.
Also- he's still aptly nicknamed "Halfway"... he made about 15 retrieves on doves after the shot and only made it half way back before he dropped them. I think if they squirm in his mouth it freaks him out. He only makes full retrieves for Wags the dog whisperer apparently.