Unless it's hot, they ignore it. Most will step on it as they walk past.
BUT....once it goes hot and they step on it and get zapped on the bottom of their foot......of those I've seen get it....most will launch about 5 feet in the air. After that, they fear it and will not cross it. They can easily hop over it, but most don't. As they are being trained they get out, and in a panic to rejoin the flock, they will pick up or hop back over to get back in, but not to routinely get out.
This seems to be the case with a lot of animals. They could easily jump over it, but once shocked, are reluctant to go airborne to find out what is on the other side as my guess is most assume when they come back down, a shock like the last one they got is waiting on them. Only way to avoid it for sure is to not cross over to the other side to find out. The negative reinforcement of a hot electric fence being that strong.