Flame Body for hatching eggs?

Question

So I got a Phione and a Ditto from a kind friend, and I began breeding. I found that Fletchinder/Talonflame with Flame Body helped hatch the eggs more quickly, but then I tried a slugma with flame body and it didnt help. What gives?

Other info:
Both were at the head of my party
The Talonflame was Japanese, I got from wobder trade as fletchling with big pecks
I used dexnav to get slugma

Comments

Are you sure the slugma has flame body?

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Are you sure it didn't help, but rather, you were hatching eggs with more cycles?

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You said "Both were at the head of my party", were you expecting the effect to stack (double)? Because it doesn't work like that?

Answer 1

I can only think of 3 cases. Note: Flame Body and Magma Armor both halve the number of steps needed for the Egg to hatch. The Big Pecks Fletchling would have originally evolved into a Flame Body Fletchinder/Talonflame and the place the Fletchling was originally from doesn't matter, so there's nothing wrong with it.

1. The effects don't stack so 1 Flame Body/ Magma Armor Pokémon=same effect as 2 Flame Body/Magma Armor Pokémon. You might have thought the effects of the abilities stack, and assumed the ability didn't work
2. The Slugma has neither Flame Body nor Magma Armor. Since you got that Slugma through DexNav, it could have a chance of getting it's Hidden Ability Weak Armor and not its normal abilities Flame Body or Magma Armor
3. As DA830 said, you were hatching a different Pokémon. Each Pokémon takes a different number of steps and Egg Cycles to hatch. You should try with the same type of Pokémon.

Source: Pokédex pages of Fletchling, Talonflame, Slugma, Magma Armor and Flame Body