with difficulty,
once they are above 6 months and generally grown, their wattles and combs will change colour, depending on wether they are in lay, or have gone off, they are in lay when their wattles and combs are bright red to show the cockerel they are ready, and they will fade out of lay, so he does not bother them.
however there are always exceptions, but wattles and combs, as far as i know dont keep growing, just change colour.
i am sure a more experienced keeper will possibly be able to advise you, they will be along soon, as its raining.
lol