Lav Orpington: late bloomer or something else?

[Ajp23]

I have four lav orpingtons that hatched the same day, all seven months old. Six of them began laying right after the five month mark but one of the girls has yet to lay an egg. Her comb is much less developed and far paler than the others. Could this be a case of a late bloomer chicken or could something else be going on?

She eats and interacts normally, she is spunky but definitely at the bottom of the pecking order with the older group. Any ideas are appreciated!

 

[MysteryChicken]

She's just taking her time, & probably start laying next month.