Can a dog who had puppies get pregnant by their 1 year 4 month old puppy
yes, it is called inbreeding and the puppies can have serious health issues.
yes that is possible. it is likely to occur espesially if alwqys together. i suggest getting both fixed or seperating them.
Oh god... think happy thoughts...
Yes! I'm surprised it hasn't happened already!
Probably. It happens.
Why oh why wasn't she spayed?? How unfair to the in-bred puppies and mother and "son"!