It's breeding season! In Minecraft, that is.
Many tech mods add fancy ways of automatically breeding up those animals which can be bred. But I wanted something more subtle, something more vanilla-feeling, for the same task. And so I created Breeding Season.
Download: https://dl.dropboxusercontent.com/u/11662651/Minecraft/Mods/BreedingSeason.zip
Breeding Season makes a few minor changes to breedable mobs' behaviors:
1) They will eat and breed from the correct item entities on the ground now. For example, a horse will breed from a dropped golden carrot or golden apple, a cow or sheep will breed from a dropped wheat item, etc.
2) For those animals who breed with items which can be blocks (i.e. crops or flowers), they will break those blocks when walking over them and begin breeding that way as well. NOTE: If you don't want this, perhaps because of the broken blocks, you can turn off the mobGriefing gamerule to stop this behavior.
3) Baby animals are now afraid of the dark. This means that if they can get to a brighter spot within 5 blocks of their current position, they'll run there, even ignoring their parents or owners (baby pets will still teleport to their owners when out of range, but they won't walk into darker areas). This allows you to easily separate adults from babies while breeding: as long as the adult pen is darker than the baby pen, they'll separate themselves.
Some notes: All breeding requirements still apply. This means dogs still won't breed unless they're tamed and at full health, etc. When an animal is in breeding mode ("in love"), it won't consume any more items or blocks until it's done breeding and ready to begin again; so if you drop a stack of wheat by a cow, for instance, it'll only eat one and not the whole stack.
Of course, since droppers can drop those items on a clock, this means breeding can now be fully automated using plain old redstone! The design for such a farm, including how to control lighting for baby separation, is up to you
Download: https://dl.dropboxusercontent.com/u/11662651/Minecraft/Mods/BreedingSeason.zip
If you have any ideas for things to add to future versions of this mod, please suggest them! I hit a creative block trying to come up with more; keep in mind it should be vanilla-styled but still enhancing the process of breeding.
And of course, all comments are welcome below!
(And lastly, this won't work with other mods' mobs, only vanilla ones. I may expose a few methods to make it mod-compatible in the future, if it's popular enough.)