Lynne
Am I right that Royal Canin is a dry food?
My puppy, Paddy, is now four months old and had exactly the same thing: soft pooh, that over time became diarrhoea, with blood and mucus in it. He was eating normally, but without much enthusiasm on Nutro, a dry food that's got a good reputation, and over time (from about 11 weeks) he began to eat less and less of it. Throughout, he was perky, sweet and lovely. When the blood came into the equation, I took him to the vet, along with a sample of the offending pooh. When tested, it was clear of bacteria and worms.
Vet said (as the other posters have said) that it's colitis, an inflammation of the gut, which reduces his uptake of nutrients and calories. Paddy had continued to put weight on throughout, until the last few days when he was only eating 40g of food per day, instead of 240g! Vet says it's a permanent sensitivity to dry food - it's indigestible for him - since there's no bacterial or worm cause for Paddy.
I'd noticed flakes in his fur. Vet gave me anti-biotics (kills any bacterial cause but also works as an anti-inflammatory on the gut) and four days' worth of a Royal Canin tinned wet pet food (only available from vets) which is highly digestible (and painfully expensive - about £2 a tin!). He then recommended that I put Paddy straight onto Nature Diet when the Royal Canin wet food was finished - no "lead in" etc.
For the first time, I have a pup who is wolfing his food down, his flaking has all but stopped, coat's shinier - and see my other post about Nature Diet - they're having supply problems, everywhere's sold out and they're not scheduled to make any more puppy food for six to eight weeks! As an alternative in the meantime, I'm using the adult "Original" variety (identical base ingredients, recommended by my vet) plus (as per vet's instructions) scrambled eggs to make up the protein difference four times a week. I've ordered a "Puppy Life Stage" food by Forthglade (don't bother with their website - years out of date!) which is apparently virtually identical to Nature Diet.
I'd second what the other posters have said: get Murphy to the vet. Colitis could be a temporary problem caused by bacteria or worms, or it could be a permanent sensitivity caused/aggravated by dry food. Remember the pooh sample!
Good luck.
Denise