At 60 days, the eye color should change. As soon as they get tertials, you should be able to sex them, which would be about 2 weeks before the eye color change.
from Sam Carney's wing age/sex determination manual.
Age Determination of Males
Immature tertials are pale bronze with pointed, usually frayed, tips. Immature tertial coverts are narrow and yellow-green. Most immatures replace both tertials and tertial coverts with dark blue adult-type feathers by late October. As the immature middle and lesser coverts are replaced by the adult-type plumage, the presence of a few dark blue feathers among the duller coverts indicates immaturity. Usually, the dark blue does not extend onto the third row of coverts and is much restricted to the area anterior to the proximal half of the secondaries. Generally, coverts of adults are somewhat wider and tend to lie more smoothly on the wing and the dark blue usually extends on to the third row of coverts and extends farther distally than on wings of immatures.
Age Determination of Females
Immature tertials are pale bronze with pointed, usually frayed, tips. Immature tertial coverts are narrow and yellow-green. Most immatures replace both tertials and tertial coverts with purplish red adult-type feathers by late October. Usually, the blue iridescence is confined to two rows of coverts and is restricted to the proximal half of the immature wing. Adult coverts are somewhat wider and tend to lie more smoothly on the wing. Dark blue usually extends onto the third row of coverts and extends farther distally than on the immature coverts.
Clint
