Added in 6651b1b (MOBSPAWN trigger) using the "spawnedby: EGG" condition.

It may be a stretch to consider mob spawns as a "drop" but in reality it adds a lot of power and flexibility to Otherdrops.

Not sure that fits the concept of the plugin...

Was led to believe that egg throws drop chickens sometimes? Haven't seen it myself but this is a low priority and would only run the eventlistener if a config was added.

They do drop chickens sometimes, but that's a bit different from blocks and creatures dropping things, isn't it?