
How much in total does he get a day and eat.
My dogs that weigh 20kg as adults get at most 200g a day of Arden Grange.
Chances are that your overestimating how much he needs.
If his condition as opposed to weight is not as good as you w9uld like (skin, nails and coat) then I would only then change his ffood to a richer one, otherwise he sounds like he is doing great.
Also you shoudl not feed straigh6t after excersise, even though bloat is a probelm mainly of large deep chested breeds, it isn't a bad idea to not feed a dog for an our before or after excersise as it coudl give them indigestion, therrby making a picky dog even less inclined to eat.