I stopped chopping when my leopard was about 2 months old and I got lazy one day. I put a bunch of larger leaves in the bowl, and watched it use its front legs to hold them down as it violently tore chunks out of them. Maybe that's what those spikes on the legs are for? To help with feeding? I noticed when it rips off a piece that's too big it will drag its arms across its mouth to break it off.
The only thing I continue to chop is cactus pads since it won't touch larger pieces. I chop it as fine as possible and mix it with the Mazuri every couple days.