Sex links are sexable at birth, so what you have is actually "hatchery reds", also known as "production reds", most of the time just referred to as "Rhode Island Reds".
Most of the Rhode Island Reds in the US today were crossed years ago with leghorns to create what the hatcheries now call RIR.
This created a lighter carcass, but heavier laying bird... great for lots of eggs.
However, they continued for all these years to call them Rhode Island Reds, even though most of them have leghorn in them from way back when.
The other "slip of the tongue" that happens a lot with several breeds including the RIR, is that just because a breed is a "heritage" breed, it doesn't mean the birds you receive are from heritage lines. A lot of folks think that just because there were told they were getting RIR, that they were getting heritage birds. In reality, most are not.
I can't tell you the number of people who have said to me, "But I have heritage RIR" - as in "they are RIR and the RIR breed is a heritage bird". If they came from TSC, or a hatchery I assure you they are not heritage birds - which is fine, as they are awesome layers. It's just that the terminology has been so misleading for so long that most folks really don't know.
This has also caused the folks who really do have old, true heritage lines to begin using the term "Heritage" in front of the name.
But be aware, just because the term heritage is there doesn't mean that most folks really know what they have.
But suffice to say, those who have heritage birds know it because they can trace the line back years and years - in my case, 2014 is the 100th year.
But once you see the 2 side by side you will likely think they are very different birds.
This is sometimes taken as snobbery by folks who simply do not know, but I assure you as I have gotten to know the heritage RIR breeders, it is meant as education, not snobbery. They are some of the nicest and most helpful folks I know.
Mostly the HRIR folks really just want the old lines carried on... and without the education of how to do that then those lines will die.
OK... enough RIR history for today... now that I've bored everyone to death.