#3 looks like it would sunburn; and if I had #6 I'd have to shell out around $1500 for a mate for it. So I'd go for #5 - it is so homely it is adorable.
Is number #3 a real breed of chicken? I've heard of naked necks but not an entirely naked bird! I bet the poor thing gets chilly easily. Without a doubt I would choose number #6 though, such a stunning black color!