* Aggression: Jills can be very protective of their kits and may become aggressive towards other ferrets, even if they are normally friendly. This aggression can be directed towards the other female ferret, potentially leading to injury.
* Stress for the mother: Having another female ferret around can stress the Jill, making it harder for her to care for her kits. This stress can also lead to decreased milk production or even the abandonment of her kits.
* Competition for resources: The other female ferret may compete with the Jill for food, water, and nesting space, further stressing the mother and potentially jeopardizing the kits' survival.
* Risk of disease transmission: Even if the other female ferret appears healthy, there is always a risk of disease transmission between ferrets, which could be particularly dangerous for the vulnerable kits.
It is always best to keep a new mother ferret isolated with her kits for at least the first few weeks. This will give her time to bond with her kits, establish her nursing routine, and ensure the kits' health.
If you are unsure about the best course of action, it is always best to consult with a veterinarian or experienced ferret breeder.