Fixed some small passive mob issues (#4057)

* Chickens can be bred with seeds, beetroot seeds, melon seeds, or pumpkin seeds Ref: https://minecraft.gamepedia.com/Chicken#Baby_chicken
* Baby passive mobs don't drop items
* Fixed the size of some mobs

src/Mobs/Pig.cpp

@@ -21,6 +21,11 @@ cPig::cPig(void) :
 
 void cPig::GetDrops(cItems & a_Drops, cEntity * a_Killer)
 {
+	if (IsBaby())
+	{
+		return;  // Babies don't drop items
+	}
+
 	unsigned int LootingLevel = 0;
 	if (a_Killer != nullptr)
 	{