Darker is actually better, so long as it is reddish buff. Ideally, you don't want to see that little dark spot on their head or chipmunk stripes on them. That would be an indicator of too much black showing as they mature. Lighter chicks aren't really desireable either, they tend to feather out lighter as well. I don't think the color looks too bad with yours though. Give them time to show you what they got.Just hatched a few Buckeye chicks!
There is more color variation than I expected. Some are quite a bit darker than others. Is that normal, or did I perhaps hatch an egg from one of my Barnevelder hens by mistake?
Also, some have dark spots on their head. Is that a variation of color, or is it a clue to gender?