Canarys stopped Breeding this year

[Milliemoo]

Hello
I need some advise on my canaries please. Last year they successfully reared 4 nests, totalling in 10 babies. it was all going like clockwork. They are outside in a large aviary, and this was their first breeding season together, as I have only just started up.
At the end of the season and because my female canary was still wanting to breed, I separated the male into another part of my Aviary which I had built on especially for him.
When I put the male back in the Aviary this year at the start of the season, they have carried on to have 5 nests all with 3 eggs, but none of them are fertile.
The 2 Birds get on very well, and he was feeding her while on the nest.
Is this normal please? I don't know which bird isn't fertile anymore, so
I thought I would get another female canary, at the end of the season.

Please could you tell me when would be the best time to add a female, either now or early next year.
I will be putting the male back into his side of the Aviary very soon.
Thank you

[Dave]

Milliemoo,

If the female lays eggs, she is most likely not the problem. Although there could be an internal problem with her, too.

Some breeders give the male a little extra vitamin E before / during the breeding season.

Do you manage the day length, so they have a fall and winter period where the day light gets shorter; and then a spring where the day light gets longer?

Are they in a mixed aviary? Sometimes another (jealous?) bird will disrupt the male as he treads the female.

I'm sure there are a lot of other possible causes.