18 week old ISAs, Easter Egger and Partridge Rock- no eggs yet!

[Hannah_banana]

Hello all, This is my first time raising chickens and I have 4 18 week old birds. 2 ISAs, 1 Partridge Rock and 1 Easter Egger. I was wondering when I should be expecting to get our first egg. I know ISAs are prolific layers so we keep checking every day and nothing yet. I kind of figured we would be seeing an egg soon. Their combs are super red and getting bigger every day and they’ve become super chatty lately. Any other signs I should be looking for? How about for the Easter Egger and Partridge Rock? Thanks in advance! Pics attached if that is at all informative.

My partridge rock's didn't starting laying until they were 7 months old. My Easter eggers 1 started laying at 8 months and the other at 10 months. Not sure of the ISA's. My first partridge Rock lays medium size eggs, my other partridge Rock lays large eggs , my Easter eggers lay large eggs.