I rescued three kittens from the street the other day because their mom died and they are stray cats so i took them home until i find someone who wants to adopt them. I noticed somethings a few days ago that there is one kitten that has a red anus, like red and a bit swollen, i didn't know the reason until i found his brother biting it, or literally sucking it. i do not know why but it hurts him so much and i do not know their gender yet. but they are so young, small kittens. then after afew days i found the third one's anus swollen and red too and i noticed the same one biting and sucking it. which is really annoying.. please help??