Sick chickens but don't know what, HELP!?

[xIndigoSkyx]

So I'll give you a list of symptoms, how long it's been happening, what I'm feeding them etc. 

-6 White Leghorn hens

-Got them in January

-Fed chicken scratch and layer feed

-VERY scruffy looking, dirty looking, feathers missing on a few 

-Some have kind of swollen crops

-White stuff caked around vents of some

-Eats allot amounts of food

-Lays normally but very low hatch rate

-Lives with 9 other chicken's; 1 rooster, 1 sex link hen, 7 adolescent leghorn hens. 

-Open range, caged at night 

If you can give me an answer to whats wrong, that would be great! 

 

[nurse_turtle]

I would start with a lice and mite check. Look at the bases of the feathers under and around the vent area to look for tiny light brown adult lice or clusters of hard white eggs. If that's negative, I suggest worming the flock.

 

[xIndigoSkyx]

I give them lice check every month so I think the worming them would work. Thank you for your help.