Your dog is getting into something it shouldn't be, likely outside. When he goes out watch closely and see what he is eating. Whatever it is, it clearly needs to be stopped. It's just going to be you watching closely all the time.
Hi Thank you for your response. It turned out my daughter gave him half a slice of protein bread with linseed as he was watching her eat. Obviously it doesnt agree with him, maybe cos he is raw fed. thanks again but all is good now
So glad you found the cause! Ours are raw fed as well, and we had a similar incident a few months back when my husband was cooking bacon, and gave one of the dogs several slices uncooked, since he saw them as raw. They are, however the sodium content in bacon.....cannon butt all over the walls a few hours later.... Lesson learned for him.