Or, to add to your little edit there, have the rarity or chance of more Houndour eggs diminished. Like maybe out of those eight eggs, have three Houndour and five Rattata. I'm sure people already employ an idea like that when they make eggs posts, but the fact that rarities are just as common as the Rattata defeats the purpose.

So something like, just as a template:
Common x Common = Common
Common x Uncommon = 50% Common, 50% Uncommon
Common x Rare = 70% Common, 30% Rare
Common x HARD MODE Rare = 90% Common, 10% HARD MODE Rare