This is a test of commonsense. Complete the next sentence:

How to breed cockatiels 
Make sure your cockatiels are old enough. 
For breeding purposes, your male and female cockatiel should be at least 18 months old. Younger females may experience problems like egg binding and younger birds also may not take good care of their babies.
Egg binding is a condition where the eggs become stuck in the cloaca. This may lead to an infection and even death.