Are these chicks the correct size?

[Newbie_Chicken_Lady]

Hello, I am new to owning chickens and this is my first time raising chicks. These chicks are about 15 weeks old. They are not bantams and I will list the breeds. 2 leghorns, 1 ISA Brown, and 1 Asian Black that are about the same size. I was wondering if anyone could tell me if they are the correct size for their age. This is just worrisome for me because they are only about 5 weeks away from laying eggs and look a bit small. And yes I realize that not all chickens start laying at exactly 20 weeks.
P.S. My rooster is wearing a collar because we live in a subdivision. It does not seem to be hindering his growth and we take it off at night. The reason you are able to see it is because he freaks out when he can’t see it.
Here are some pictures. My hand can fit on the main part of their bodies. Demonstrated in the first and second pictures. Thanks for the help!

 

[sourland]

Birds are in apparent good feather and health.

 

[JacinLarkwell]

They look fine size wise

 

[Newbie_Chicken_Lady]

Thank you

 

[Dragonfly1976]

I have 4 leghorns that are 10 weeks old. Yours look about the right size for being 5 weeks older then mine

 

[Gray Farms]

I see nothing to worry about.