Sorry for the grim thread but I really need advice. My darling girl dog was pts suddenly and unexpectedly a few weeks ago. My old boy is, sadly, much happier with the extra attention and treats.
So, background. He has trouble digesting protein so is on a prescription diet. But he does love his food and I have been treating him a bit more than I usually do. Secondly, I went away the weekend before last and packed in a bit of a rush, so I forgot his profibre and prescription biscuits, so he just had tinned food.
To where we are now - I have noticed for the last week or so that his poo is a different colour. It is normal inside but it's dark around the outside, almost black. Almost like a sausage that's been fried quickly! No other changes, going regularly, happy in himself, just the colour on the outside of his poo is dark.
Dr Google has been no help as I can only find reference to completely black poo, not just on the outside. I'm so worried, I know I should call the vets but last time I did that my beautiful girl was gone less than 24 hours later. I;m too scared of that happening again 
Can anyone help?