How do I tell how old my new chickens are?

[buggal]

He everyone,
I just added 10 new hens to my flock 2 weeks ago. I was told that they are good layers and about 2 years old. However, they do not seem to lay to many eggs. I had a flock of 13 (mainly barred rocks) and was getting 8-11 eggs a day. Now with 10 more hens I would expect to to see at least 4-5 more a day but we are only getting a total of 10-12 a day now. Just wanted to see what the general thought is about why I am not getting more eggs.... My thought is are the chickens old, but I don't know what to look for to see how old a chicken might be.
Also I have 6 silky girls that seem young. There again I really don't know how to tell how old a chicken is but they seem young. I have had them for 2 weeks also and have only gotten 2 eggs out of the 6 and one of the eggs was with out a shell. Any thoughts would be appreciated.
I know this may sound funny but do the feathers change with age? Like with people getting older we go gray or white and our hair isn't as thick as it was when we were young. Do chickens feathers change color or texture?
TIA
Lisa

 

[sourland]

There is generally a drop in production when birds are moved to a new environment. It may be a matter of days, weeks or even months.

Yes, feathers tend to get a bit battered and tattered. This is why birds molt annually.

 

[aart]

Welcome to BYC!

At 2 years old, and at this time of year (if you are in the northern hemisphere),
not only will you have to wait for them to get used to the new environment but they may also soon molt.
You may not get any eggs until after solstice.
What breed are they?

 

[buggal]

Americana, barred rocks, buffs,and I the others are mixed breads

 

[donrae]

Welcome to BYC!

At 2 years old, and at this time of year (if you are in the northern hemisphere),
not only will you have to wait for them to get used to the new environment but they may also soon molt.
You may not get any eggs until after solstice.
What breed are they?

This.

Once a hen is mature, it gets harder to tell her age. There are some signs such as thicker legs and overall heaviness, but there's nothing really reliable.

If you were told 2 years, though, I'd be inclined to think they're 2 years old. There's not much reason to lie and say that age. If you're going to lie about how old a bird is, I'm thinking you'd say it's under a year. Shaving a year off really doesn't make much sense.