mixed flock, old and young. how will i know when pullets lay first eggs?

[Acie]

have 4 pullets. how will i know if they have started laying yet? i have 5 older hens that are still laying daily. all 9 hens lay brown eggs, so i wont be able to tell by the color. i check daily the new hens to make sure they havent prolapsed... idk why im super paranoid about that. is it even possible to tell when one has laid their first egg? all the new hens faces are bright red now. i havent noticed any squatting but i honestly dont think i will know what that even looks like till i see it.... how will i know if my new hens have laid?

 

[dekel18042]

When new ones start laying, their eggs are usually smaller (pullet eggs) then increase in size. (Although I had one who started with a huge double yolker, poor chicken. I knew it was a different chicken because the hue was different.)
Even if you have hens that lay the same color egg you can often tell them apart, can be a slightly different shape or different tint. Sometimes hens will start with darker egg colors that fade a bit as they get into laying.
There's also a chance as they start you will notice you are getting more eggs. Keep a record of the eggs you get now and you will see an increase.

 

[Acie]

I saw one of my pullets in the nesting boxes while 2 of my Brahma hens were in there laying... I sat and peeked thru the window and watched my 2 hens lay... (First time I've witnessed an egg being laid!) I didn't notice the pullet squatting tho. But I did find this egg (in a different box than the one I'd left her in) but its smaller and lighter than what I normally get outta the brahmas... So.... What do you think? Could it possibly be from my barred rock pullet?!