My female cockatiels are laying unfertilized eggs
I have 3 female and 3 male cockatiels that are divided by pairs into 3 cages. I know they are capable of breeding because 1 pair already had a clutch of 4 babies. However, since that clutch that pair has laid 3 clutches of eggs, another pair has laid 1 clutch, and they are all sitting on the eggs.
I leave the eggs in for the correct amount of time, but when I check them at the end of that time the eggs have not hatched and do not have babies in them when I check them with a light. Some of the eggs have turned dark colors, so they are not fertile either. The other pair is laying eggs but refuse to sit on them. What is going on?