diff --git a/include/pokemon.h b/include/pokemon.h
index d5459fe76..d45912d9e 100644
--- a/include/pokemon.h
+++ b/include/pokemon.h
@@ -280,8 +280,7 @@ struct BattlePokemon
     /*0x15*/ u32 speedIV:5;
     /*0x16*/ u32 spAttackIV:5;
     /*0x17*/ u32 spDefenseIV:5;
-    /*0x17*/ u32 isEgg:1;
-    /*0x17*/ u32 abilityNum:1;
+    /*0x17*/ u32 abilityNum:2;
     /*0x18*/ s8 statStages[NUM_BATTLE_STATS];
     /*0x20*/ u8 ability;
     /*0x21*/ u8 type1;
@@ -501,7 +500,7 @@ u8 CalculatePlayerPartyCount(void);
 u8 CalculateEnemyPartyCount(void);
 u8 GetMonsStateToDoubles(void);
 u8 GetMonsStateToDoubles_2(void);
-u8 GetAbilityBySpecies(u16 species, bool8 abilityNum);
+u8 GetAbilityBySpecies(u16 species, u8 abilityNum);
 u8 GetMonAbility(struct Pokemon *mon);
 void CreateSecretBaseEnemyParty(struct SecretBase *secretBaseRecord);
 u8 GetSecretBaseTrainerPicIndex(void);
diff --git a/src/battle_controller_link_opponent.c b/src/battle_controller_link_opponent.c
index 5f842c632..53fcd1723 100644
--- a/src/battle_controller_link_opponent.c
+++ b/src/battle_controller_link_opponent.c
@@ -603,7 +603,6 @@ static u32 CopyLinkOpponentMonData(u8 monId, u8 *dst)
         battleMon.speed = GetMonData(&gEnemyParty[monId], MON_DATA_SPEED);
         battleMon.spAttack = GetMonData(&gEnemyParty[monId], MON_DATA_SPATK);
         battleMon.spDefense = GetMonData(&gEnemyParty[monId], MON_DATA_SPDEF);
-        battleMon.isEgg = GetMonData(&gEnemyParty[monId], MON_DATA_IS_EGG);
         battleMon.abilityNum = GetMonData(&gEnemyParty[monId], MON_DATA_ABILITY_NUM);
         battleMon.otId = GetMonData(&gEnemyParty[monId], MON_DATA_OT_ID);
         GetMonData(&gEnemyParty[monId], MON_DATA_NICKNAME, nickname);
diff --git a/src/battle_controller_link_partner.c b/src/battle_controller_link_partner.c
index 86ae2a572..d03d73e3c 100644
--- a/src/battle_controller_link_partner.c
+++ b/src/battle_controller_link_partner.c
@@ -488,7 +488,6 @@ static u32 CopyLinkPartnerMonData(u8 monId, u8 *dst)
         battleMon.speed = GetMonData(&gPlayerParty[monId], MON_DATA_SPEED);
         battleMon.spAttack = GetMonData(&gPlayerParty[monId], MON_DATA_SPATK);
         battleMon.spDefense = GetMonData(&gPlayerParty[monId], MON_DATA_SPDEF);
-        battleMon.isEgg = GetMonData(&gPlayerParty[monId], MON_DATA_IS_EGG);
         battleMon.abilityNum = GetMonData(&gPlayerParty[monId], MON_DATA_ABILITY_NUM);
         battleMon.otId = GetMonData(&gPlayerParty[monId], MON_DATA_OT_ID);
         GetMonData(&gPlayerParty[monId], MON_DATA_NICKNAME, nickname);
diff --git a/src/battle_controller_opponent.c b/src/battle_controller_opponent.c
index d94b47423..5dc4fb335 100644
--- a/src/battle_controller_opponent.c
+++ b/src/battle_controller_opponent.c
@@ -586,7 +586,6 @@ static u32 GetOpponentMonData(u8 monId, u8 *dst)
         battleMon.speed = GetMonData(&gEnemyParty[monId], MON_DATA_SPEED);
         battleMon.spAttack = GetMonData(&gEnemyParty[monId], MON_DATA_SPATK);
         battleMon.spDefense = GetMonData(&gEnemyParty[monId], MON_DATA_SPDEF);
-        battleMon.isEgg = GetMonData(&gEnemyParty[monId], MON_DATA_IS_EGG);
         battleMon.abilityNum = GetMonData(&gEnemyParty[monId], MON_DATA_ABILITY_NUM);
         battleMon.otId = GetMonData(&gEnemyParty[monId], MON_DATA_OT_ID);
         GetMonData(&gEnemyParty[monId], MON_DATA_NICKNAME, nickname);
diff --git a/src/battle_controller_player.c b/src/battle_controller_player.c
index 71b1f690d..af9f2a487 100644
--- a/src/battle_controller_player.c
+++ b/src/battle_controller_player.c
@@ -1671,7 +1671,6 @@ static u32 CopyPlayerMonData(u8 monId, u8 *dst)
         battleMon.speed = GetMonData(&gPlayerParty[monId], MON_DATA_SPEED);
         battleMon.spAttack = GetMonData(&gPlayerParty[monId], MON_DATA_SPATK);
         battleMon.spDefense = GetMonData(&gPlayerParty[monId], MON_DATA_SPDEF);
-        battleMon.isEgg = GetMonData(&gPlayerParty[monId], MON_DATA_IS_EGG);
         battleMon.abilityNum = GetMonData(&gPlayerParty[monId], MON_DATA_ABILITY_NUM);
         battleMon.otId = GetMonData(&gPlayerParty[monId], MON_DATA_OT_ID);
         GetMonData(&gPlayerParty[monId], MON_DATA_NICKNAME, nickname);
diff --git a/src/battle_controller_player_partner.c b/src/battle_controller_player_partner.c
index 2a877e584..e8ac30990 100644
--- a/src/battle_controller_player_partner.c
+++ b/src/battle_controller_player_partner.c
@@ -673,7 +673,6 @@ static u32 CopyPlayerPartnerMonData(u8 monId, u8 *dst)
         battleMon.speed = GetMonData(&gPlayerParty[monId], MON_DATA_SPEED);
         battleMon.spAttack = GetMonData(&gPlayerParty[monId], MON_DATA_SPATK);
         battleMon.spDefense = GetMonData(&gPlayerParty[monId], MON_DATA_SPDEF);
-        battleMon.isEgg = GetMonData(&gPlayerParty[monId], MON_DATA_IS_EGG);
         battleMon.abilityNum = GetMonData(&gPlayerParty[monId], MON_DATA_ABILITY_NUM);
         battleMon.otId = GetMonData(&gPlayerParty[monId], MON_DATA_OT_ID);
         GetMonData(&gPlayerParty[monId], MON_DATA_NICKNAME, nickname);
diff --git a/src/battle_controller_recorded_opponent.c b/src/battle_controller_recorded_opponent.c
index a495db835..f7394e9b5 100644
--- a/src/battle_controller_recorded_opponent.c
+++ b/src/battle_controller_recorded_opponent.c
@@ -585,7 +585,6 @@ static u32 CopyRecordedOpponentMonData(u8 monId, u8 *dst)
         battleMon.speed = GetMonData(&gEnemyParty[monId], MON_DATA_SPEED);
         battleMon.spAttack = GetMonData(&gEnemyParty[monId], MON_DATA_SPATK);
         battleMon.spDefense = GetMonData(&gEnemyParty[monId], MON_DATA_SPDEF);
-        battleMon.isEgg = GetMonData(&gEnemyParty[monId], MON_DATA_IS_EGG);
         battleMon.abilityNum = GetMonData(&gEnemyParty[monId], MON_DATA_ABILITY_NUM);
         battleMon.otId = GetMonData(&gEnemyParty[monId], MON_DATA_OT_ID);
         GetMonData(&gEnemyParty[monId], MON_DATA_NICKNAME, nickname);
diff --git a/src/battle_controller_recorded_player.c b/src/battle_controller_recorded_player.c
index 4831600f9..38aba4942 100644
--- a/src/battle_controller_recorded_player.c
+++ b/src/battle_controller_recorded_player.c
@@ -566,7 +566,6 @@ static u32 CopyRecordedPlayerMonData(u8 monId, u8 *dst)
         battleMon.speed = GetMonData(&gPlayerParty[monId], MON_DATA_SPEED);
         battleMon.spAttack = GetMonData(&gPlayerParty[monId], MON_DATA_SPATK);
         battleMon.spDefense = GetMonData(&gPlayerParty[monId], MON_DATA_SPDEF);
-        battleMon.isEgg = GetMonData(&gPlayerParty[monId], MON_DATA_IS_EGG);
         battleMon.abilityNum = GetMonData(&gPlayerParty[monId], MON_DATA_ABILITY_NUM);
         battleMon.otId = GetMonData(&gPlayerParty[monId], MON_DATA_OT_ID);
         GetMonData(&gPlayerParty[monId], MON_DATA_NICKNAME, nickname);
diff --git a/src/battle_controller_wally.c b/src/battle_controller_wally.c
index 5473a9881..9c3662e66 100644
--- a/src/battle_controller_wally.c
+++ b/src/battle_controller_wally.c
@@ -486,7 +486,6 @@ static u32 CopyWallyMonData(u8 monId, u8 *dst)
         battleMon.speed = GetMonData(&gPlayerParty[monId], MON_DATA_SPEED);
         battleMon.spAttack = GetMonData(&gPlayerParty[monId], MON_DATA_SPATK);
         battleMon.spDefense = GetMonData(&gPlayerParty[monId], MON_DATA_SPDEF);
-        battleMon.isEgg = GetMonData(&gPlayerParty[monId], MON_DATA_IS_EGG);
         battleMon.abilityNum = GetMonData(&gPlayerParty[monId], MON_DATA_ABILITY_NUM);
         battleMon.otId = GetMonData(&gPlayerParty[monId], MON_DATA_OT_ID);
         GetMonData(&gPlayerParty[monId], MON_DATA_NICKNAME, nickname);
diff --git a/src/pokemon.c b/src/pokemon.c
index 4ae81c653..b5a095aa2 100644
--- a/src/pokemon.c
+++ b/src/pokemon.c
@@ -4293,7 +4293,6 @@ void PokemonToBattleMon(struct Pokemon *src, struct BattlePokemon *dst)
     dst->speed = GetMonData(src, MON_DATA_SPEED, NULL);
     dst->spAttack = GetMonData(src, MON_DATA_SPATK, NULL);
     dst->spDefense = GetMonData(src, MON_DATA_SPDEF, NULL);
-    dst->isEgg = GetMonData(src, MON_DATA_IS_EGG, NULL);
     dst->abilityNum = GetMonData(src, MON_DATA_ABILITY_NUM, NULL);
     dst->otId = GetMonData(src, MON_DATA_OT_ID, NULL);
     dst->type1 = gBaseStats[dst->species].type1;