Try to remember when

[3Xgranny]

How old are hens when they start laying? Are there any chickens that have large combs.

 

[Blue Raptor]

How old are hens when they start laying? Are there any chickens that have large combs.

About 18 weeks is when they start laying eggs.

 

[nuthatched]

How old are hens when they start laying? Are there any chickens that have large combs.

Depends on the breed, anywhere from 5 months to 8 months, some breeds have larger combs, usually males have larger combs and wattles. Are you sure you have females?

 

[3KillerBs]

Average age for laying could be between 18 weeks and 6 months.

Some of the Mediterranean breed girls have impressive combs.

 

[U_Stormcrow]

A bird will lay when it lays. You can't set a calendar by it, or even block out a given week. Some breeds tend to be early, some breeds tend to be late - but individuals will buck the trend. My earliest bird laid just before 18 weeks. My latest bird, after 31.

Comb size is determined by genetics. Shape, too. I don't pretend to understand chicken genetics, will leave it to others to explain it.