It wasn't until several minutes later that I made the connection: my cat is providing for his "family." He's gotten used to chickens being in the house, he headed out to the coop, rather than hiding out, the night the raccoon came through (but didn't get in), and has slept with baby chicks playing around him, inches from his nose. So it makes sense that he would be providing for them, like they were his kittens.
If he could have gotten in, he might have brought it to them. Chickens...ah, have a taste for rodents. That's putting it a lot more delicately than the feeding frenzy that erupts if they catch them. And I remember when I uncovered a rat nest behind some stuff in the coop, a couple years ago. It wasn't pretty. Little veloceraptors feasting on rodents. Why am I having visions of cooperative hunting parties of chickens and cats?