Hi all, same kitten similar issue.
My kitten is now ten weeks old and when he came to me he was on whiskas and go-cat. When I started to add Felix he got blood in his poo. Straight away I went back to whiskas only, and also gave him chicken and he had a couple of chicken and rice meals from the vet. It's been a week and the poor thing still has blood in his poo. The vet checked him over and decided it's an inflamed colon, he sometimes has no blood and sometimes has very obvious drops, and his poop is still soft. He can't have pro-kolin cause it gave him the runs, amazingly.
He has three days of de worming with panacur and that did seem to help, but now he's not on it anymore it seems to have started again.
I'm starting to add Felix again because even without it, his poo has been soft, and I'm starting to think it's the whiskas after all (a similar thing happened to my older cat and my cousin's kitten), and I'm going to get him some more chicken and royal canin sensitive.
Ha anyone got any further advice? While I would normally be straight to the vets, they aren't concerned at all because he's bright and happy and healthy, and the next port of call for him anyway would be a poo analysis as they don't want to give him any antibiotics for some reason. So any ideas what I can do at home for now?