While a bird of any species can be affected, there are a few types of birds that seems to be prone to egg binding, most notably Cockatiels, Parakeets (Budgies), and Lovebirds.
Egg binding is a serious problem that requires swift medical attention. Left untreated, an egg bound hen can suffer nerve damage, shock, paralysis, and even death.
Common symptoms of egg binding include rapid breathing, swelling, constipation, fluffed up feathers, and straining. Egg bound hens may also be unable to perch, and may take to sitting in the bottom of their cages.
If you notice your bird exhibit any of these signs, you should contact your avian veterinarian immediately for an exam. As with other avian illnesses, time is of the essence. The quicker that an egg bound bird receives medical attention, the better her chances of recovery and survival.