I prefer to leave crushed egg shell out for my birds all the time, then supplement their seed diet with vegetables and pellets. It is best to introduce the new foods before the chicks hatch. This allows the parents to become used to the new food so that it does not interfere with their feeding of the babies. The last part of the breeding equation is light. Birds need at least twelve hours of light, artificial or real, for them to believe that it is breeding season.
Longer days give the birds more time to feed their young, as well as signal warmer weather.
Even in the climate controlled environment of a house, birds still anticipate the longer days of spring and summer. So, you've thought about the care, housing, and breeding of your new birds. Let's take a look at some different finch varieties. The three most common species of finches are the zebras, societies, and spice. Most pet stores have at least one of the three varieties for sale, and these are the finches that breeders most often have in abundance.