Quick note: This would only give a lioness one more litter on average in her lifetime, so wouldn't be a strongly overpowered mutation

Not sure if this is a great mutation idea or an awful one! In real life, this sort of thing wouldn't really be a mutation but a variation among animals, but since no such feature is present in Lioden I think it would be best handled as a passable mutation with a chance of - for example - 5% or 10% naturally

One issue that I generally have with mutations is that they are mostly cosmetic only and don't serve any particular purpose, which means they can be easily devalued. The ones that can pass naturally have more value generally since they have some practicality. But the only mutation that has a genuine practical purpose so far to my mind is double uterus.

This could potentially be some sort of similar mutation to DU in that it wouldn't have any visible traits, and naturally it would be an adult only mutation. However, the lioness - having a shorter cooldown than other lionesses - would come back into heat sooner in 16-18 days (could be randomly generated), which over the course of her lifetime would allow her roughly one more heat.

After delivering her first cubs, there could be flavour text that would read,

"[Name] looks at you and batters her eyelashes. She tells you she's not ready for any more cubs just yet - but she's not quite sure she can wait another year and a half either!"

Since this would just be a mechanics mutation rather than a visible one, it shouldn't take nearly as long or as much artwork to code as a completely new mutation.

Thoughts?