Well they are some kind of partridge color I think. Usually shows up by the chipmunk striping in the chick down. I wonder if these are Speckled Sussex?.  Or Welsummer? At any rate I think you will see some pretty birds when they feather out.
Get a small bottle of Bovidr Labs Poultry Nutridrench at Tractor Supply or your feed store. 
www.nutridrench.com
Put one and one half teaspoons in a quart waterer for the next 2 weeks. This will get them off to a strong start. No need for anything else in the water. Give them some Greek yogurt for probiotics.
What feed are they getting?
Best,
Karen