Hi, I have a week old litter of 6 Siamese kittens. 5 Seem normal and plump but the 6th kitten is underweight but eating and making the usual noises. What really worries me is that his genital area is a dark red/brown colour. I thought it was dirty so wiped it with a damp piece of cotton wool but of course it wasn't. I haven't a clue what this is. Does anybody have any idea please?