Interesting, I've never heard that about the guineas
My friend that suggested getting them for bug control has always had them all free ranging together without problems. To be honest hers don't even stay entirely on their property. Mine so far though barely want to leave the run. They fly out over the fence only to spend the rest of the day stupidly banging their head into the fencing repeatedly trying to get back in
One actually broke his own neck and died running away from me as I tried to catch him to help him into the run.

I tried to raise them in a way that would tame them but it didn't happen. They are total psycho freaks...
Hatchery guineas are like that. Also guineas from lines that have next to no human contact. I have seen guineas that come from lines that have been hand raised (like you would a pet chicken) for about 3 generations that hold trust in their humans and are not psycho freaks.
There is an inherited memory/instinct that takes several generations to collect and override the wild instinct. The experiences of the parent is passed to the young in genetic coding. In Mustangs off the range it takes about 5 generations to loose the wild reflexes and that is only if nothing happens to support the wild reflexes. Example: my friend had a mustang stud that was the foal of my mustang mare. She was breeding him to her mares. She went out to feed them in the winter with hay in the back of the truck. Now I had raised this stallion and he was extremely pushy but didn't seem to pass this on to his foals. Correction. "Extremely pushy" is an understatement. If you didn't dominate him every second he would forcibly take control sometimes in ways that would get you hurt.
This day she had her 13 year old niece with her. They got in the back of the bed to throw the hay out. Now Cactus Pete (the stud) had this disconcerting trick of rushing up to you and flipping around for you to scratch his butt. If you had never seen it before you would swear that he was preparing to kick your brains out. Even so I had to fight my own reflexes a couple of times when he did it and make myself stand still. Well the niece screamed and Pete kicked the truck. The niece screamed again and Pete whirled around with eyes flashing and teeth bared. My friend, standing above him in the pickup bed spread her hand and tried to calm him with her voice. He came halfway up into the pickup truck and bit her breast. Thank God he released it instead of tearing it off but she carries the scars to this day. He then proceeded to kick the pick up some more before herding all the mares off to the other side of the field.
Now can anyone guess why he went bonkers?.......
Don't feel bad if you can't because it took me a week and a half of reviewing everything I knew about Mustangs and the conditions they live in on the range to put it together.
1. What is the Mustang's No. 1 predator? The cougar/mountain lion.
2. What does a mountain lion sound like? A screaming woman.
3. Where/how does a mountain lion attack? They leap from above.
4. What is their first attack weapon? Spread claws.
5. What is their second and fatal attack weapon? teeth
What happened? A scream (from the niece). They were standing above him and my friend spread her fingers and held up her hand and opened her mouth to talk to him. Claws and teeth from above. That was when he attacked. She could not have pushed more of his wild instinct buttons if she had tried. Now because those instincts are reinforced it could be longer than just 5 generations for any offspring born after him to loose that.
Now this information has not gone through the rigors of scientific research yet. But I have consulted with many horsemen who work with Mustangs and they all agree on what they see. I have come to believe that this genetic memory is present in other species as well. Most notably you can find information from people who breed wolves and wolf-hybrids. In fact I had tried to explain to my friend (who raises Wolfhounds) the likeness between Mustangs and wolves: that you had to think like one of them so you didn't accidentally trigger wild instincts. She thought she understood what I meant but she didn't. By the way if you are worried about the fate of Pete, he was given to a horse trainer who had him gelded and eventually broke to saddle for his daughter. Once the high testosterone levels cleared his system he wasn't such a control freak. I was glad because he had the makings of a great horse (athletic and totally fearless) but I wasn't able to take him there because I had a disk in my neck go bad and had to have surgery.
But to link it back to the guineas I believe it possible to establish bloodlines of tamer guineas if you have the patience to hand raise them like pets. Mustangs after a few generations of not having their wild instincts triggered are not so reactive. Now if you are more than four hours late in bringing them their feed you are still likely to find them grazing on your front lawn when you come home, but the more extreme reactive responses diminish. I currently have a couple of Olive Eggers that hatched under duress. Out of 150 eggs only three hatched because of a power failure. They are very nervous and skittish which is very different from the others that are from a different hatch. I believe it was because of the conditions which they hatched that they believe the world is out to get them. I even named the pullet Chicken Little for the way she is always sure the "sky is falling".
Has anyone else noticed behavior like that from survivors of a distressed hatch?