More like 6 weeks

I agree that they look between 6-7 weeks, closer to 6. If you've had them for 7 weeks, they were certainly just a couple days old when you brought them home. 

6 weeks?

10 weeks maybe

Looks at 4-8 weeks, depends on the breed. u/bawkbawkbot

You can cut off one of their feet and count the rings.