My canary has 3 eggs I don't know when they were laid?

I noticed she was spending all day in her nest and so a few days later while she was out I peeked in and saw 3 eggs in there. I don't know when they were laid so how do I know when they will hatch? This is her first clutch so how likely is it that they will be fertile? I have 2 females and a male together in an aviary with 2 male zebra finches will the other female get lonely if I separate the couple? I didn't even know my two canaries were a couple until I saw the cute little eggs! Any advice appreciated. This is my first experience with eggs!