African Grey - mating behavior????

Question
Rev. Abbott....
I am the proud owner of a wonderful African Grey female named Coco.  I adopted Coco (who came from a very loving home and was in no way abused or neglected) six months ago.
She is smart, funny, active, a great companion. She is eight years old. Within the last two weeks her behavior has noticably changed.  I suspect it is mating/nesting behavior, but I'd like to confirm that suspicion and perhaps find out what to do, if anything.
When she is in her cage she is now spending virtually all her time on the bottom of the cage, on newspaper she shreds, sitting on or near a small metal bell and attached plastic-link chain.  She is squatting down, and generally her feathers are puffed up.  For the first six months it was very difficult to get her back into her cage, as she wanted to stay with me at all times, following behind me as I went from room to room.  Now however, she stays in the cage even when the door to it is left open.  
In addition, she has stopped doing her droppings in the cage.  She will wait all night, holding it in, and only when I take her out in the morning will she release an enormous dropping.  Ditto for during the day.
She is not ill, and is her usual perky, chatty, adorable self when I coax her out of her cage...but after a short while she walks back and climbs into her cage -- something she NEVER did before.
She has not laid any eggs.  Is that a concern?  Should I be concerned about her being egg bound?  What would be the signs?
As I said, I'm virtually certain this is laying/mating/roosing behavior...but what should I do about it and how long will it last?
Thank you for any insight you can provide.

Answer
Peter, I appreciate your concerns and have to agree with you that this isn't quite normal.
 If this were just nesting behavior, I wouldn't expect the constant fluffing of feathers or even the constant desire to be in the cage like that.  Even nesting birds will venture out now and then, plus the feather fluffing isn't something you'd see except on occassion.

Keep in mind that birds are masters at hiding illness.  Her normal behavior once you coax her out isn't necessarily a good measure.

I'd have her seen by a vet who knows birds (preferably an avian vet, but quite a few of the regular DVM's know birds quite well).  It would be worth the peace of mind.

As for egg laying/egg binding, take a look at how to prevent this and what to watch for at my site

www.4AnimalCare.org  (click on the bird tab)

You sound like a very involved, loving parent and I want very much for your girl to return to her normal self, following you around the house again!  

Please let me know how it goes, ok?