Ollie is not on good form today. He is limping around on three legs, and his usual happy expression has deserted him. He has almost certainly pulled a muscle in his thigh, after chasing a deer at great speed a couple of days ago. It looks so sad, to see him holding up the leg as he tries to get around.
Even his curly tail is at ‘half-mast’!
But I am guessing that when he sees his lead appear soon, and knows it is time for his walk on the nature reserve, he will forget the pain.