Ice and fire mod has a mechanic where chicken mobs will have a chance to lay a rotten egg instead of a normal egg after 5 mins, and yes, chickens mod mobs are also counted. However, chickens inside nesting pen will ignore that mechanic

So my request is, if it possible, have vanilla chickens and animania roosters and hens to lay rotten eggs inside the nesting pen, but the egg rate can be configured, so, before the chickens lay it should look at the rate first.

I will look into this. but technically hatchery should be able to catch their drops.

Edit: I'm guessing the property gets removed somehow. possibly during a world reload. not sure yet. May be a while before I get this figured out.

Understandable, even that mod is having issues with their mechanic on vanilla and animania chickens