cockatiels dont get along

Question
Hi, I bought a cockatiel 2-3 years ago, and he is very friendly.  When he is in his cage, he comes up to me and puts his head down to get cuddles with my nose, and when he's out, will cuddle with me for long periods of time.  My sister had two older cockatiels for a long time before me, about 10 years, and they were great friends and lovers, they laid eggs together, and cuddled all the time.  She also had two new  lovebirds that she kept with the cockatiels sometimes.  And one day, she left both cages open, and left all 4 birds together in the same room.  When she came home, she found the male cockatiel dead on the bottom of the cockatiel's cage, and the female was fine sitting at the top.  There was blood splattered around the cage on the walls and the dead bird had peck spots at the top of his head.  My sister thought that her lovebirds killed the bird, as they are extremely aggressive birds.  Needless to say, I decided to take the female cockatiel who is around 16-17 years old now.  My cockatiel is only 2-3 years old as when I got him, he was only a few weeks old.  I've had the birds together now for almost a year now, and they still haven't taken to each other.  My bird used to bite at the female all the time, and chase her, but lately, the female is egg-bound I think.  She has had an egg in her belly for a couple of months or so.  I've tried putting her in the bathroom, in a box with some sugar water, warm towels under her, with the warm water running to make it warm in there, but nothing seemed to help.  As for my bird, he has been so stressed out with her, I don't know what to do with him.  I don't know what's going on in the cage, but I've been waking up to alot of flapping around in the middle of the night.  And whereas my bird used to be the one that showed dominate behaviour, it seems that all of a sudden, he is scared to death of the female.  He has recently started pulling his long feathers out under his left wing.  I found them all at the bottom of the cage, some of which had small dabs of blood on the tips, and he is acting very nervous around her.  He isn't coming as quickly to cuddle with me anymore, as he is watching her to see what her next move is going to be.  She seems very friendly with me now.  This is odd, as she has never been a very affectionate bird.  My bird has no long feathers left under his left wing, and cannot fly for the first time in his life.  Is it possible that the female bird killed her other mate at my sister's house, and that she is trying to kill my baby?  Please help me try to figure this out, I'm at a stand-still. Thanks so much,  Angie


Answer
Hello Angie and thank you for your post.
To start with, if your female Cockatiel is egg bound, then she needs to be seen by a Certified Avian or Exiotic Animal Vet right away for surgery as this is always a fatal condition for females.
It was more than likely the Lovebirds that killed your sister's male Cockatiel.  
You need to seperate the two Cockatiels.  It sounds like they are not getting along, and if your male has become a feather plucker, this is more than likely a stress issue.
You can keep their cages side by side, but the two really do need to be seperated.
It is not unusual for the females to become dominent and push the males around a bit, and if they're fighting in the middle of the night, this is not a good sign.
Another thing that you might be hearing at night is one of them having "Night Frights".  This is not uncommon for Cockatiels, I have a female that gets them.  Leave a night light on for them at night to help stop the night frights.

Good luck and God Bless.
Dianna