Runt? Help!

[MattalynsBarn]

So one if my 16 day old chicks is about half the size as the other chicks. She has some other health problems (Has trouble pooping, the vet concluded she's not drinking enough) that we're treating. Is she a runt too? Are there any problems that go along with being the runt? None of the other chicks pick on her

but I don't know anything about runts

 

[Tomhusker]

I got 4 Lavender Orpingtons a couple of weeks ago. One was HUGE, another was very small, less than half the size of the other larger one. Today, at 3 weeks old the size difference is about the same, but the runt is doing just fine. It does look sickly, with thinned out fluff and being small and all, but it eats, drinks and battles for treats with the big ones just fine. I call it/her Raggedy Ann.