I agree that if your Welsummers are flighty or aggressive then I would think that their breeding is suspect. I've had Welsummers for a number of years and while they are not a "friendly" breed they are extremely calm. Even my roosters have never shown the slightest agression any time I enter their run. I've also found they are the easiest on their hens of any breed I own and my hens to not exhibit the slightest bit of "rooster wear".