Dwarf chick?!

[MelissaRose]

I got five Welsummer and Barnevelder chicks from a guy who had gotten them from a breeder and then realized they weren't the kind he wanted. I brought them home and they were happy and healthy, and one of them was a little smaller and I said oh well some chicks are just small, I had chick hatch this spring that was a little smaller and now she just the same size as the others! this chick should be fine.
the other welsummers and barnevelders grew an she grew a little and now their almost five weeks old and she's half the size of them and they have more feathers than she does, here are some pics

she is the little one with less feathers, their in the grass so its harder to tell
Does anyone have ideas why she might be like this and is there anything I should be doing for her, is it okay for her to be with the bigger chicks hatched in march and silkies they just moved in with today?

 

[FeatherstoneFrm]

I have an Australorp cockerel that did the same. Half the size of the others and very slow to feather. He is fine and now about the same size as my pullets but smaller than the other cockerel. He is clearly 2nd in command in the pecking order. They are 14 weeks old now

 

[MelissaRose]

I have an Australorp cockerel that did the same. Half the size of the others and very slow to feather. He is fine and now about the same size as my pullets but smaller than the other cockerel. He is clearly 2nd in command in the pecking order. They are 14 weeks old now

I assume that is what will happen with mine.