French red leg Partridge sexing help

[Arvor25]

I already have Chuckars but I know have some French red legged but how do I sex them
I have 5 young ones I hatched but how long before I can sex them
None of them have the lump on the back of the leg as a Chuckar has

 

[ylly]

The male will end up a lot bigger. The little lump will be also bigger when it grows in.