Can a 5 year old hen have a healthy brood?

[calrose]

My only Buff Orpington hen is about 5 years old. She had stopped laying eggs awhile back, but then we got a rooster and her egg production started back up. I can tell the buff's eggs are fertile when I crack them open. Should I attempt to incubate some? Or is she too old?
My first incubation of 6 eggs (4 reds, and 2 from buff) only 1 Red chick hatched.

 

[JacinLarkwell]

Absolutely I had a 7 year old start brooding last year. 2 clutches that year