Awe, poor Artemis! So her very first family just dropped her off at a friend's house and never came back for her? What is wrong with people...honestly. But if she didn't start plucking until after going to her second family, then it's pretty self-explanatory as to what caused the plucking to begin with...And even if she did start the plucking towards the end of her time with her first family, chances are that it started due to neglect, boredom, and not getting any time out of her cage, no interaction with people, probably no toys or foraging activities, etc. I'm guessing this based on the fact that they simply dropped her off at a friend's house for whatever reason and then just never came back to get her; based on their total lack of care for her well-being or any feeling of responsibility for her, I'm guessing that the end of her time with her first family was probably not the best. In my experience at the Rescue with cases like this, where people have simply abandoned their bird after having them for some length of time, it's usually the case that the people were very excited to get a parrot (especially if they were the bird's first family and got the bird as a little baby), they often do very little research into the time, attention, interaction, and care that a parrot requires all throughout it's life, for decades, and after the initial "new car smell" wears-off, they realize that they have no desire to be parronts, no desire to give their bird time out of the cage every day, and often they even have trouble just putting clean food and water in their cage every day, they stop cleaning the cage, they put the bird in a back bedroom out of the way, where the bird often goes days without even seeing a single person in the house, and the bird becomes a piece of furniture. I see this all the time; sometimes the people are at least responsible enough to admit that they just don't want the bird and the bird deserves better, and they will properly surrender the bird to an Avian Rescue or re-home the bird to people who are experienced with parrots and who they know can give the bird a loving, attentive home, other times they simply just don't give a damn about the bird, they feel no responsibility to the bird at all and think of it as nothing but a nuisance, something that drives them crazy with it's screaming, and they often go from just being neglectful and progress into being abusive, throwing things at the bird's cage or hitting the bird's cage with things to try to get them to stop screaming (out of boredom and the want for attention, and sometimes because they are starving and dehydrated due to them not feeding the bird anymore); I've seen more than a few cages that surrenders have arrived in with huge dents in the bars from the owners hitting the bars and throwing heavy objects at the cage because the poor bird has been constantly screaming and crying for attention. It's very, very sad.
So if Artemis's first family was able to literally abandon her at a friend's house and never come back for her, then chances are that she hadn't gotten much, if any attention, interaction, stimulation, or love in quite a long time, probably not since she was a little baby. This will most definitely cause plucking in any species of parrot, especially a tame, hand-raised parrot that craves human attention, and that has the intelligence of a 3-4 year-old human toddler. If they have nothing to do and no one paying attention to them, and all they do all day long every single day is sit on a perch inside of a cage and stare at the wall, then of course they start to pluck, at least it's something to do, something for them to work-on, a job. We'd start pulling our hair out and picking at ourselves too if we were locked inside a cage with no toys, nothing to read, nothing to listen to, no one to talk to, etc. And I feel for the people who took Artemis in, or I guess who had no choice but to take her in, at least temporarily, what an awful thing to have a friend do to you, just dump their pet at your house and never return for them. Some people never grow-up and are not capable of being responsible for themselves, let alone for another life.
I'm so glad that Artemis is going to your home, it sounds like you're going to really be an attentive parront. I think that's really probably all Artemis needs, a lot of love, attention, and stimulation. Senegals are such loving little birds, not a lot of people think of them that way until they actually own one, but once you have one in your life, you realize that all they want is to be with you all them time. That's all Kane ever wants, is to just be "with" me, like just on my shoulder sitting with me. I don't have to be directly interacting or playing with him, or even talking to him, he just wants to be with me. He'll be sitting in his cage playing with his toys, and when I sit down in the room to read or watch TV or play a video game, he always stops what he's doing and immediately just starts crying and whining and making kissing-noises at me, and doing our special contact "Wolf-Whistle" that we do, and I go over and let him out, and he goes right to my shoulder and is completely content for hours. He'd rather be sitting on my shoulder doing nothing than playing with his toys. They really are loving, caring, velcro kind of birds once you form a close bond with them.
And I'm soooo glad you have an Avian Specialist at your disposal! That really is priceless, you have no idea how many people have no vets at all around them for hours, and then many have totally clueless "Exotic's" Vets that can actually be worse than having no vet at all, as they sometimes so more harm than good. I have both a Certified Avian Vet and a Certified Herp/Reptile Vet, as well as a 24/7 Exotic Animal Hospital all within 10 minutes of my house, and once I started talking to people from all over the world on the forums I realized how extremely lucky I was...It's amazing that even in the US, in very populated urban and suburban areas, there are absolutely ZERO Avian Specialists, and sometimes not even an Exotic's Vet within hundreds of miles. It makes me want to go back to Vet School and finish, just so I can become both a CAV and a CRV...It's interesting, because I recently watched a lot of episodes of "Dr. K's Exotic Animal Hospital" on the NatGeo channel, and I was just blown away...I don't know if you're familiar with the show or with Dr. K and her partner Vet, but she is an Exotic's Vet, as is the other female Vet that she hired to work with her, and they treat any and all living creatures except for dogs and cats, she absolutely refuses to treat dogs or cats, because she says there isn't a need for more dog and cat vets. I was blown away watching the miracles that this woman and her partner perform on a daily basis, she even treats aquarium and pond fish! That blew me away more than anything, a father brought his two young kids in with their sick Betta Fish, and she diagnosed the fish with some kind of bacterial infection in it's skin (she actually took a culture from this Betta's skin) and she gave the Betta fish an Antibiotic injection, and then showed the father how to do it once daily at home for 7 days...I couldn't believe it. She performed 2 surgeries on extremely young, unweaned, baby Macaws who were born with extremely severe congenital deformities of their legs, where their legs were literally positioned up over their heads and sideways...She went in and cut their bones basically off, then cut them into the correct lengths, and rebuilt them using plates, screws, and pins with external-fixators...She built these baby Macaws legs! These guys are what an Exotic's Vet is supposed to be, someone who is educated and experienced with ALL species of pets that they treat; unfortunately the majority of Exotic's Vets in the country know very little at all about ANY of the pets that they treat. But if you live in the Fort Lauderdale/Miami area you are blessed because you can take whatever animal you have to Dr. K...