If you're looking for a colorful egg basket, you have to add some olive eggers. Since these birds are defined by their egg color, they aren't a breed per se, but are the result of breeding a dark egg layer with a blue egg layer. Many combinations can be used so the resulting olive eggers can have various types and personalities. For mine, I used a cream legbar rooster and various marans and welsumer hens. The progeny lay from a deep minty green to a beautiful true dark olive.
Interestingly, the mothers of my OE's all started laying between almost six months to over eight months and the daughters (Perhaps because of the legbar influence) were all laying before five months.
I do think the welsumer crosses can be sexed at hatch, just like the purebred welsumer mothers, but unfortunately I wasn't paying a lot of attention to this. I want to hatch more next year and will definitely pay more attention to see if this holds true. if it does, the welsumer cross might have an advantage over the crosses where marans were used.
I also want to try creating some using EEs. So many possibilities, so many colors.