Chicken Still Real Small?

hello.
my lastest batch of babies were born on feb. 22 2010 and i have one chicken that has remained small.
i have researched her breed. (which when i get a second here ill edit and add the name i forgot what kind)
should i be concerned? She has been eating good, drinking water and free ranging too.
She has been picked on by the others, (no blood tho) and she runs from them.
while the others go out in the run,,, she stays up on the roost in her coop.
just kinda sad for her.
shes so friendly, i call her my little lover.
as of yesterday, while sitting on an outside chair, she jumped up on my lap.
shes my sweet lil girl.
her size and growth has me a bit concerned. especially compared to her friends.
thanks again for any information anyone
o---okay the kind of chicken is called a muffled cochin? shes black and white and she has a small comb.

andrea-

 

yes i matched the picture to her. thats exactly what she is.
i feel so bad for her. like shes the outcast.