I think most all dogs keep in a kennel with others will do this.I know mine will some times. they do have some kind of a feed or pill or something you can feed you dogs that will stop that.I don' t really know what it is,I really have never been worriedabout it.I have had dogs for about 40 years and tey have all done it at one time or the other.
call your vet and he can give you some idea of what it is I' m talking about.he is going to tell you you need to buy it. because he is selling it.I never have.