papermc/paper-server/nms-patches/EntityAgeable.patch

--- a/net/minecraft/server/EntityAgeable.java
+++ b/net/minecraft/server/EntityAgeable.java
@@ -8,6 +8,7 @@
     protected int b;
     protected int c;
     protected int d;
+    public boolean ageLocked; // CraftBukkit
 
     protected EntityAgeable(EntityTypes<? extends EntityAgeable> entitytypes, World world) {
         super(entitytypes, world);
@@ -46,7 +47,7 @@
                 if (entityageable != null) {
                     entityageable.setAgeRaw(-24000);
                     entityageable.setPositionRotation(this.locX(), this.locY(), this.locZ(), 0.0F, 0.0F);
-                    this.world.addEntity(entityageable);
+                    this.world.addEntity(entityageable, org.bukkit.event.entity.CreatureSpawnEvent.SpawnReason.SPAWNER_EGG); // CraftBukkit
                     if (itemstack.hasName()) {
                         entityageable.setCustomName(itemstack.getName());
                     }
@@ -119,6 +120,7 @@
         super.b(nbttagcompound);
         nbttagcompound.setInt("Age", this.getAge());
         nbttagcompound.setInt("ForcedAge", this.c);
+        nbttagcompound.setBoolean("AgeLocked", this.ageLocked); // CraftBukkit
     }
 
     @Override
@@ -126,6 +128,7 @@
         super.a(nbttagcompound);
         this.setAgeRaw(nbttagcompound.getInt("Age"));
         this.c = nbttagcompound.getInt("ForcedAge");
+        this.ageLocked = nbttagcompound.getBoolean("AgeLocked"); // CraftBukkit
     }
 
     @Override
@@ -140,7 +143,7 @@
     @Override
     public void movementTick() {
         super.movementTick();
-        if (this.world.isClientSide) {
+        if (this.world.isClientSide || ageLocked) { // CraftBukkit
             if (this.d > 0) {
                 if (this.d % 4 == 0) {
                     this.world.addParticle(Particles.HAPPY_VILLAGER, this.d(1.0D), this.cv() + 0.5D, this.g(1.0D), 0.0D, 0.0D, 0.0D);