We have had our 2 rescue kittens for 2 weeks and I have noticed that occasionally there are spots of bright red blood in the litter after one of the kittens has pooed. They are approx. 13 week old brothers and I think it is the biggest (and very timid) of the two who is doing it. We see him drink water everyday and he likes the Hills science plan dried food more than the wet food whereas his brother eats mainly the wet food. His poo does not seem overly hard but as this has happened a few times now I am starting to worry. What could be causing it and does it need a trip to the vets? They have had their vaccinations and worming tablets (milbemax). They are eating well and are fine in themselves and not showing any signs of distress when using the litter tray.