Fertility?

[newchickmom]

When is a rooster old enough to be fertile?

My rooster is doing his thing, but the girls haven't even started laying yet.

They are 19 wks old. Australorps.

 

[bigzio]

Mother Nature has a way of knowing what works. While he isn't as potent as he will become, by the time the pullets are laying they won't be blanks.
That is the same with fertile eggs. Hens go broody at the end of the clutch, which means the eggs will be larger than the first ones layed by the young pullet. Providing plenty of nutrition with a larger yolk for the growing peep.

bigzio