It just wnt grow. It is the same size as it was the first day we got it at about 3 days old a 3 weeks ago. (we have some a month old also) This little guy walks under some of the other ones legs. It is seriously the smallest thing. It is getting feathers and looking normal except for its size. just weird. I am sure it has rear end deformity. I have cleaned its little bottom off several times and just finally gave up. It seems to do fine except poop sticks to its behind. It eats and drinks fine. Holds its own even. It is pretty tough and even steals the food away from the bigger ones. I guess we will see how things go when we put them in there coop (which I hope is soon because 30 month old chickens in the house is driving me nuts.)