Oh Birdiemom you make me want to cry!! I'm so touched, so moved by what you are going through and how determined you are. I've been crazy lucky with my little Yoda. My husband and I brought him home when he was about 8 weeks old, and he's a sweetheart.... mostly. So it's easy for me to deal with his tantrums and moody times because he's so loving and wonderful most of the time. However, just knowing how sweet and wonderful he is when he's loving and happy makes it TOTALLY worthwhile to go through the moody times that he does have on occasion. I hope that you keep sticking with him and get to the point with Felix where he is 85% angel and only 15% devil, like Yoda.
ALL of the advice that I have seen people giving you sounds like REALLY good advice, even the ones that contradict each other. Things that work great for one bird, don't work as well for another bird. And sometime things that work great for one particular bird at a particular TIME don't work as well at other times. The one thing that I believe is always true all of the time, is that time, love, tenacity, and care WILL work. Thank you for not giving up.
Now my advice, for whatever it's worth. It sounds like Felix is territorial and defensive, mostly inside of his cage perhaps, but even outside of his cage. You said he came from a family where he was poked and dare-I-say terrorized by small children, I'm sure this is why he is territorial and defensive now.
- When he's in his cage, he's thinking: "This is my home, I own this, I'm the boss here, and anything or anyone that comes near my cage is scary and probably going to do something I don't like so I'm going to chase them away." .... if he succeeds in chasing you away, he learns that it works. He's rewarded. Yoda sometimes gets like that if I reach into his cage, because of his time at the pet store where people reached in and grabbed him all the time, so I try to avoid reaching in to get him, and instead I hold a treat over my finger and call "Come here Yoda!" which he mostly responds to quickly. If not, I just leave the door open until he comes out on his own and then we can go from there. I only reach in to grab him I really need to get him out of there (cleaning cage, time is critical, or he's just not cooperating with the other methods). I almost never need to resort to that anymore.
- When he's out of his cage doing his own thing and you are nearby but not TOO close by, he's probably perfectly fine and happy. He's thinking "I'm safe and warm and my flock is right there where I can see her, but nobody is messing with me. This is good. I think I will take a nap." However... eventually he'll get bored or hungry or lonely or maybe just very itchy because of all those pin feathers coming in. At those times he wants more from you. He might come at you or call out to you, and then you have to figure out what he wants. He will probably come at you while trying to inform you that he is the boss and you need to do something for him. Strutting, puffing up, trying to look tall, squawking and biting are all ways that he can "put you in your place" as he lets his demands be known to you.
- When he's out of his cage and you get close to him, he doesn't know WHAT he wants you to do or what you WILL do. He's going to start with his default behavior above, to let you know he's the boss. If he's bored or hungry, he wants you to give him food or toys or just entertain him as he squawks and bites and threatens you until he's done with you and you go away and leave him alone. If he's lonely or feeling really itchy because of all those pin feathers, he wants you to cuddle and love him and give him attention... but he doesn't know that's what he wants. Sure, he HAS cuddled and been petted and loved by you, but he's still expecting that anything or anyone that comes near him is going to be scary or poke him or grab him. This is just the trust and bonding that will come over time.
Keep showing him that you will NOT be driven away and intimidated, but also that you will NOT be scary, pokey or grabby. He'll learn in time that when you come around it means love, cuddle, treats, itch-relief, and is a good thing. He also needs to learn that YOU and your SO are the Alpha and not him. You're not afraid of him, his bites will not get him what he wants. Either by putting him on the floor until he is sorry (NOT a reward, because the floor is not his favorite place, it's not his cage or his favorite perch), or by holding his beak (NOT a reward, obviously), he will eventually learn bites don't work. Keep him nearby while you are home doing your own thing (like you are, sounds like the new cage location by your desk is perfect!), and he's learning that you are his flock and you provide food, warmth, love, and safety. Keep encouraging his good behaviors with treats, as that seems to work for him, try associating the treat with a sound or vocalization. Some people use clickers, but I prefer to just say "Good boy!" in a really super-sweet almost baby talk way. He likes that sweet soothing sound, and Yoda is certainly learning that hearing me say "Good boy!" that way means all good things, even when I don't have a treat handy.
For me, Yoda is molting and he gets cranky sometimes because he's itchy. He's got pin feathers all over him and it can't feel very nice. He's crabby and nippy and doesn't SEEM like he wants me to hold him, but I encourage him onto my hand (treats helped train him to Come Here!) and gently rub his face, his cheeks, the top of his head, and he melts into a pile of VERY VERY happy happy loving warmness.
Just don't pet or scratch too hard, sometimes if I accidentally pet into a pin feather and it gets pushed into him, that does NOT feel good and he yells, and sometimes that results in a full-blown angry bird. Petting with the grain or gently zigzaggering back and forth with the grain is safer. As Yoda has grown to trust me more, I'm able to gently scratch his pin feathers to help them open, which he is SO grateful for, but I have to be careful and not hurt him of course. Baths and humidity can help him with his itchiness, but nothing beats some gentle, helpful petting.
Good luck! Keep at it! Felix is SO lucky to have you, and in time he'll be worth every minute you spent earning his trust and his love.
