While no one here would ever attack you for considering to rehome your bird, the negativity is going to come because this poor bird was set-up to fail just simply based on the multiple homes and different owners. So the first thing you need to understand is that hand-taming a bird starts with first, before anything else, EARNING THE TRUST OF THE BIRD, WITHOUT THIS IT'S IMPOSSIBLE TO TRAIN THEM; AND THIS BIRD HAS BEEN GIVEN NO REASON TO TRUST ANYONE. THAT'S WHERE YOU'RE STARTING FROM.
First of all, before we can help you, can you please answer some questions the best you can, as you didn't really provide any information about the bird or it's history at all. This is important if we are going to be able to help you at all:
-What species of bird is this?
-Do you know how old this bird is?
-Do you know what gender this bird is FOR CERTAIN? (without a DNA test it's impossible with some species, with others you can tell by looking at them, it just depends on the species)
-Do you know how many owners this bird has had?
****-Do you know if this bird was hand-raised/hand-fed by a human as a young baby by a breeder, or was this bird raised by it's parents with no human interaction until after it weaned? IT WASN'T A WILD-CAUGHT BIRD, WAS IT?
-Was this bird ever bonded to another bird of the same species, or a part of a breeding-pair of birds at any point?
****-Can you explain what you have done in the way of training/taming exercises in the almost year since you've had this bird? Have you spent a good amount of time every single day with this bird doing hand-taming training? Do you give this bird ample hours every single day of time out of his/her cage, in a room with a shut-door? IS THIS BIRD FLIGHTED OR ARE IT'S WINGS CLIPPED? WHERE DO YOU HAVE THIS BIRD'S CAGE LOCATED IN YOUR HOUSE? IS IT LOCATED IN THE ROOM OF YOUR HOME WHERE PEOPLE USUALLY ARE LOCATED, WHERE THE "ACTION" OF THE HOUSE IS, LIKE THE LIVING ROOM, FAMILY ROOM ETC., OR DO YOU HAVE IT'S CAGE LOCATED IN A BACK BEDROOM, SPARE BEDROOM, ROOM THAT IS OUT OF THE WAY AND NOT WHERE THE PEOPLE IN THE HOME SPEND MOST OF THEIR TIME?
If you could please answer these questions to the best of your ability, we'll have a much better picture of what's going on and what is the best way to approach taming/training your bird. YOU NEED TO UNDERSTAND THAT HAND-TAMING/TRAINING A BIRD THAT IS NOT TAME AT ALL AND WON'T EVEN STEP-UP, AND IS BITING, ESPECIALLY ONE THAT HAS HAD MULTIPLE HOMES/OWNERS TAKES A LARGE COMMITMENT EVERY SINGLE DAY FROM YOU. This process can take months and months to years to accomplish, but this is what is going to be required to first earn this bird's trust, and then get the bird to be receptive to training time with you every single day, as well as out of cage time with you every day...YOU ALSO NEED TO REALIZE THAT SOMETIMES IN SITUATIONS LIKE THESE IT IS NECESSARY TO CLIP THE BIRD'S WINGS TO START THE HAND-TAMING PROCESS. Some people disagree with me on this, but as someone who has hand-tamed dozens of non-tame Budgies over 30 years, I can tell you from experience that the easiest and quickest way to earn the trust of a bird like this is to take away it's ability to fly. By doing so you are essentially forcing the bird to RELY ON YOU, AND IN ORDER FOR THE BIRD TO COMPLETELY RELY ON YOU FOR MOST EVERYTHING, EVEN FOR SIMPLY THINGS LIKE GETTING BACK TO IT'S CAGE FROM THE FLOOR AFTER TRAINING TIME, IT MUST TRUST YOU. IN ADDITION, IT'S NEARLY IMPOSSIBLE TO MAKE PROGRESS IN HAND-TAMING AND TRAINING TIME IF THE BIRD SIMPLY KEEPS FLYING AWAY FROM YOU EVERY TIME YOU GO NEAR IT. All that ends-up happening in this common scenario is you spend your hour or two of daily hand-taming/training time, in the room you have chosen as the training room, one with a carpeted floor and a latching door, running around chasing the bird from picture frame to picture frame, window or curtain rod, etc. AND THE MORE YOU CHASE A BIRD AROUND A ROOM, THE LESS IT IS GOING TO TRUST YOU, AND THIS IS ACTUALLY MAKING YOUR TRAINING GO BACKWARDS INSTEAD OF FORWARDS...FOR THESE REASONS, THE FIRST THING I DO BEFORE I START HAND-TAMING/TRAINING A BIRD LIKE THIS IS TO CLIP IT'S WINGS...
