Hi,
As others have said Dad needs removing from Mum as he can get her pregnant staright away. This is called a breedback and isnt good for Mum as she will be using all her resourses for feeding the new babies.
Please dont remove any of the babies from the mother, baby males can not get mum pregnant and only need to be removed by 8/10 weeks but 12 weeks at the very latest..
Chinchillas can breed from as little as 5/6 months old so having a male/female pair together means they will breed. They will continue breeding if Dad goes back into Mum. It is not advisable to breed a female chin thats under 1 year.
Dad needs to stay out till the kits are at least 7 days old, but Mum will come back into season in about 4 weeks and would end up pregnant again.
Please ask your sister to consider having dad castrated, lots of vets can do it and he would need to stay away from the female for 6 weeks after castration.
Kits will need weighing daily, at roughly the same time to ensure mum is feeding them enough. They will lose a few grams each day, but should start to put on weight by about day 3.
If you need any other advice feel free to contact me at
[email protected]
or come and join us at chinsrus.co.uk.
Unless the chins your sister has, are pedigree chins with full history background, then its really not advisable to breed from them as heredity conditions can occur.
Edited to add, Mum needs her sandbath withholding for seven days, as she can get an infection as she will remain open down below for roughly seven days.