X3. I jumped 3 nets together to enclose about 1/3 acre.
No.
The bottom strand is not hot. The rest are. So the bottom strand can touch the ground.
They don't think that way. Instinct tells them to come up and sniff the fence to investigate it. That is when they get a huge correction and are very unlikely to attempt to enter the pen.
One hard pop from the fence is going to deter them from ever coming back. That's why it's so important to power the netting with a very strong charger. I run a 10,000 volt, 1.2 Jewel, well grounded charger. Thus far, it has kept all ground predators out of the pen including the local black bears.
I do not. I have a very large run with a solid roof on it that the chickens can run into for protection. There is also a huge old style Quince bush out there that the flock can completely disappear under. And, until recently, I've always had a rooster on the lookout for them. In the over 6 years my flock has been 10-week-old pullet that was about as far away from aeriel protection as she could get.