I think I've got some advice... Hopefully it helps

I adopted 2 - 10 year old Parrots - a Blue & Gold female and a Green Wing male. They were both bonded and had layed eggs, but didnt possess the "classic signs" of a "mated pair"... Just bonded.
Both were hand-raised by a couple who were pretty violent... Meaning they had alot of domestic violence problem. Both birds picked up swearing and would also be aggressive towards eachother as-well as their owners and would "re-enact" out what their previous owners would do to eachother.
After they had left that home, they were then purchased by an elderly 71 year old lady. She had them for 7 years then when she was 78 and could barely take care of herself, I adopted them.
Now, this lady really tried her best at taking care of them. BUT they were very viscious towards her and would attack her constantly... So she devised up a system to keep them from attacking her... This is where the broom hitting, squirt gun squirting, screaming and swearing came into play. If the birds tried to attack her or did something she didnt like or want them to do, she would hit them with a broom, swear at them, hit them or squirt them with a squirtgun. This only made them more mad and had made them try to dominate her even more. They would also bite her very badly and she had to get stitches quite a bit from both birds biting.
--- So I took them home after driving 3 hours to pick them up. I was at a complete loss as to what to do because my Orange Winged Amazon was my first "problem bird rescue". Now... I had 2 that needed work and were much bigger, with much bigger beaks!
I left both birds alone for 72 hours when first getting them... In Chet Womach's eyes this would be a BIG mistake! Then after the 72 hours (only going in to check their food and water), I brought their cage out into the livingroom. I left them in their cage for a week and only talked to them for that entire week (changed their food and water of-course), then the day that I was going to clean out their cage (I clean cages every Sunday), I let them out.
Now... These birds figured that if they sat HIGHER than you... Then they were higher than you in their "flock"... Another mistake the elderly lady did. So, I put their perch only 3 feet off the ground, that way I was higher than them. I cleaned their cage, and put them immediately back into it without touching them of-course and watching their every move as both birds were flighted.
I spent the next 2 months letting them out of their cage every morning then talking to them all day. After awhile the Blue & Gold female wanted to interact more and more with me as she gained my trust. One day she was on the floor walking around, so I picked her up and put her on my shoulder for probably 2 seconds before she flew off. I then rewarded her. After another month of rewarding her for being on my shoulder for however allotted amount of time, she started coming out of her shell then wanted to spend more time with me. After she was a "pro" at being handled and learned alot of cool tricks such as "bow", "dance", etc., she was rehomed as she was very aggressive towards the male - my Green Wing.
Now my Green Wing took longer to adapt because his personality was more reserved and anti-social. I also had to watch his body language quite a bit because he was the "biter" out of the two. He only recently started allowing me to handle him and do pretty much everything you can do with a bird. He now does alot of tricks and LOVES to be handled. He HATES to be put down and would rather spend time with "mommy". If I leave the room, he screams "MOM!!!" It's quite cute actually.
SO after this HUGE novel... My advice is to take the bird out of it's cage everyday and talk to it, allow it to get familiar with you then when it's ready to... It will want to be handled and you can then teach it to "step up", etc. as I had to do with the B&G and my Green Wing.
Just a suggestion... I know most people want to handle their birds right away and not wait months on end to do this. But I feel it is the best way to have a rescued bird get to know it's new owner, surroundings, etc. I feel the bond if done this way is more stronger... Both my OW Amazon and Green Wing have chosen me as their "mate"... They regurgitate food up for me and try to feed me... Not a pretty sight but it means there's a good, trusting bond there. They allow me to stick my fingers in their beaks, pet under their wings, pull their wings outward to "preen" them and so much more. Both are not what I was told they would be - they dont act how I was told they would... They're much more friendlier, cuddlier and just absolute loves.
Both birds are VERY cuddly, love to give kisses and cant wait to spend time with me everyday.
I tried Chet Womach's (supposed to be a really good Parrot Training Teacher) Parrot Training "Techniques"... Purchased close to ALL his video's and tried them on the Macaws as-well as a Parakeet, a Dusky Conure and a Cockatiel for several months... I can definitely tell you hands-down that these techniques dont work. - His approach is to "jump right into" getting the bird to try to come to you using "treats" and a clicker... Instead of trying to allow the bird to get used to it's surroundings first, then slowly start to allow the bird to gain your trust.
Im not saying that they "couldnt" work. Im saying that in a few different birds and over a course of months... They didnt work for me or several other friends and family that have tried it.
**I have NEVER been bitten by any bird that I have worked with or have had... With ONE exception... A store-bought Parakeet who liked to "chew" on my hands just before "stepping up". Never broke skin though, he just liked to chew

So patience, time and effort is key
