If they are molting they won't lay until they are finished. Most take about a month. You really should read in the raising chicken section. It will tell you all about it. What about the others? What is different about them. Btw I don't know anything about leg color meaning they should lay.
Honey, Their legs being yellow does not help. I see they are 2 years. What about the other questions asked? Here are a few more... Are they looking a little ratty? Meaning are they loosing feathers? They might be molting. Have you added anyone new lately? We really want to help you Dear. We need...