A J-clip is a little strip of metal with a hook in one end so it looks like a letter J
When you close it with the right pliers, it curls into a small tube, wrapped around the wires you are trying to connect.
Here is an Amazon listing with a nice clear photo...
I think that is a definite improvement. For one thing, it's probably sturdier. And depending on how you attach other things to the panels, they might be fairly easy to take apart and move at a later date (when you quit renting that particular house.)
This is one place that a cutesy little prefab coop might be good. They often have plenty of nestboxes but not much space for anything else-- which is just fine if you only need it to hold nestboxes and LOOK like a coop, and the chickens never really have to spend time inside.
I would check any...