Sorry, I didn't mean to hit reply....anyways...I have a small flock of 3 different sets and I allowed them to free range around 3 months of age. I know this isn't what you asked as I don't work, I'm always home but mine do pretty well. I'm outside A LOT and they start out by always watching where I am and following me around alot. Eventually they wander farther and farther from me but look for me/run to me when they are nervous. Unfortunately, I lost one to a hawk last year, it seemed to only bump her but hard enough I think she died of shock. By the time they are 6 months, I have been known to run errands if need be without putting them away. We had a big problem with dogs running around last year so it was a CONSTANT effort to patrol and run off dogs (the owner said if I don't want to deal with free roaming dogs to movensure into city limits). The hawks, fox, racoon, coyotes, cats, and whatever else wasn't as difficult to monitor as those pesky dogs!
By 6 months of age I was impressed with how well my girls had monitored their environment and how well and quickly they were finding cover until I got to them.