I have several older birds.
11 yr old Buff Orp
3 10 yr old Cream Legbars (1 of them gave me 2 eggs recently!)
2 9 yr old mixes EE x Wyandotte and EE x Cream Legbar
2 7 yr old Black Copper Marans
I agree with the others in that you are doing nothing wrong. Not every bird will...