I am a little concerned about this little one. it is almost five weeks and is probably 1/3-1/2 the size of the other five chicks who were all hatched the same day. There is also no comb development at all. It does not seem to be sick in any way. It is lively and active like the others. I do not know what breed it is, so could it be a breed that is that much slower to develop than all the rest? There is feather development though, so that seems like a good sign. You can see in the first picture, it is the tiny one in the middle that is so much smaller. The other pictures show it up close. Should I be concerned as long as it is not acting sick?