I was converting a barn once, in an old farmyard. Every morning, we would walk past a family of five swallow chicks happily perched on a beam.
One morning, we walked in to see five decapitated bodies lying on the ground, and a farm cat not trying too hard to look innocent.
We scooped them up and gave them a burial. Silly, really, but what more can you do?
The cat did, partly redeem himself later by catching several rats in the corn mill.