Zena's Lightning Network technique didn't just affect the monkeys that were charging at those kits. It had also affected the other beasts in the area.
In reality, a spherical barrier formed in the entire area. Nearly all the beasts that had come to attack them were trapped in that spherical barrier.
This spherical barrier had been formed using Zena's Beast Lightning. All the beasts who were lucky enough to stay out of this barrier did not attempt to breach it.
The beasts possessed low intelligence, but their instincts were extremely sharp. These instincts had been honed by betting their life in every battle.
Many beasts were reliant on their instincts. They would typically avoid places where their senses told them there was danger.
Zena didn't target them since she had her hands full while dealing with the beasts inside her Barrier.