I don't bother to shred any of the leaves I rake up. The chickens will take care of theirs. The ones I put in the garden pack down and make a fantastic mulch.
I just went out to the garden to bury some bones from the bone broth I made. (They're too big for the chickens, don't want them in the compost, don't give them to the dog, and they've been brothed about 6 times already.) I dug into the leaf layer that's been there for 2-3 years, and just underneath is some NICE soil. The leaves really help keep the weeds down in that bed. It's the "I didn't get ANY butternut squash this year" bed*, a big flat area that would be full of weeds, so the leaves really help keep that area clean until the squash vines take over.
*I'm going to try to embarrass that area into producing better next year. The squash bed is bigger than some people's entire garden, and it gave me nada. (Grrrr.)
don't leave anything cooked outside. that attracts rats.