Aww, 4 little hands sounds sooo cute, but yeah, that fence probably won't stop them...

I've heard of people using smooth acrylic sheets, but I haven't tried it myself.

I usually just let them play in a closed room. They rarely defecate outside, but they do bite things. 👉🐀

If you mean fancy rats instead of guinea pigs, they will🥺. Rats loooove to climb, even when they were young they were excellent climbers.