Sexing Olive Eggers?

[Turnipseed]

I'm in the process of hatching my first ever chickens. I have Marans, Cochins, Cream Legbars and Olive Eggers on day 7 of incubation. The Olive Eggers are a Marans/Legbar cross, though they're coming out of green eggs so I assume they're at least F2. Considering the Legbars are auto sexing, is there any way to even partially tell the sex of their crosses at birth? I would like to get a handle on how many boys I have as soon as possible.

 

[Gray Farms]

F2 won't be sexlinked. You'll get the usual outcome of aprx 50/50.

 

[drumstick diva]

x2 Gray Farms