Are there physical signs they’re due to start laying?

[nep big red]

we have 5 Rhode Island Reds and 3 Orpingtons. They were all purchased at the same time as chicks and shouldn’t be more than a week apart in age.
Two (2) of our Rhode Island Reds have “floppy” combs - and it appears they are the 2 egg layers that began about a week ago. The other 3 have combs, but aren’t as developed. The Orpingtons have tiny combs.
Would I be able to use their comb size and maturity as a sign that particular chicken is going to start laying soon?
What about the Orpingtons?

 

[ChickenGirl555]

Every chicken is different, especially in breeds, but I think the biggest sign is their combs turning red.

 

[sourland]

Comb size and reddening are signs of the onset of laying. In my experience Orpingtons mature somewhat more slowly than RIR, and comb enlargement is not as significant. Squatting on the part of he hens generally indicates that egg laying will start within a week or two.

 

[aart]

..and here's more clues:
https://www.backyardchickens.com/articles/who-is-laying-and-who-is-not-butt-check.73309/