Mine used to get softer poohs after I gave them Drontal - not green though, just softer with mucous (sorry) for a pooh or two.
He's not been eating sheep pooh or similar has he as that can produce a nice green effect!
I haven't changed brands - don't want to use Milbemax because I have a collie and also as it affected all the dogs, I figured it couldn't be because one didn't get on with it. I wondered if because their poohs are usually Naturediet firm, it was more noticeable than with some other foods.
I have found something though - I bought some probiotic powder from Vet UK (via the Oldies Club link

) - and I tried giving them this with the feed that contained the Drontal and then the next day (and sometimes the day before the tablet too) and it helped significantly, their poohs are now normal/very close to normal after being wormed. Great news as I hate giving them something that makes them loose
