Smallish Tallbird Raised from Egg Aggro-ing after Re-Launching Server

Try dropping some food on the ground. Smallish tallbirds go nuts when they're hungry, trying to kill anything nearby to get some food. 

It's also a common issue that mobs you befriended lose their attachement after a rollback- it was an unfortunate discovery with my broken clockworks that threw themselves at me as soon as the server loaded. 

I had loads of seeds on the ground for him before; the aggression happened before a rollback originally, I had simply disconnected from the server and reconnected. There's no way it was because he was hungry due to the seeds I spawned in so he didn't starve while I was trying some things, and I hadn't done a rollback before the original aggro, I had to kill him originally as I didn't realize what was happening so figured rolling back wouldn't do anything other than fix the issue or reproduce it to record...