Mands
For your 4 birds, I would just make ONE egg.
Here is a trick that Liz taught me.
After you cook the eggs, peel the shell off the egg, then put the peeled egg into the fridge for a few hours. The fridge dries out the egg a bit, so it isn't so sticky/soft when you chop it up.
I try to cook in the day, leave it in the fridge for 5 hours, then chop up the egg at night.
The corn meal is simply to absorb some of the moisture that was not dried off in the fridge. For 2-1/2 eggs, I use about 2 teaspoons of cornmeal. The amount that I need depends on how long the eggs were able to dry out in the fridge. So for 1 egg, I would start with about 1 rounded teaspoon and adjust from there.
I use a mini-food processor to chop up the eggs, but if you don't have one, just use a large SHARP knife on a large cutting board. I use a large cutting board cuz it can get messy.
The egg will last 2 or 3 days.
Dump the egg if it starts to smell bad or feels slimy.
I do as Debbie said, I spread the egg out on a dish, so it will dry during the day, rather than stay wet and spoil.
Non-breeding or non-molting birds get egg only 2x a week.
Breeding birds get egg 2x day (morning and evening) and 3x on the weekend if I'm home (mid-day). I adjust based on how much they eat to feed the chicks.
Molting birds get egg 1 or 2x a day.
I put veggies (lettuce, carrots, chard, etc.) in the bowl with the egg food.
For birds which are laying eggs, I also sprinkle egg shells on the egg food every day as they are laying and for a week after.