Why did my female beagle kill her baby pups

Question
I want to know why my female beagle killed her babies.
She is about 1 year and a half maybe just over she had babies twice the first time she was not even a year old and she killed all the babies exept one this was when she wasnt even a year old. The vet said to wait till she was a year old first then leave her in the garage or laundry my garage is a room with lounge by the way she sat on the leather chair we did as the doctor said put the lights of and close the door and minimize the noise then we went to sleep next morning we found out that she killed all the babies except 1 why does she do that she ate alot of healthy food juring her pregancy allmost all the chicken in the house lol. A breeder told my mum that she was supposed to be with her the opposite of what the doctor said to do  and she said that my mum is supposed to help her take out the sack since she has a small body and the babies were large. I remmber the first time my puppie had her babies she got the first baby my mum moved it abit to the side so there is room for the next one then the female dog took the baby to its house and ript it apart the thing is why does she leave only  1 baby and the baby she leaves is smaller than the big healthy looking ones thank you .

Answer
Hi Victor

There can be a number of factors to cannibalism.  Commonly a female is bred too young and the maternal instincts aren't developed or the pups where unhealthy.

A young mother should never be alone to whelp. If she has confidence and trusts in her people, she is better able to cope and is reassured when she has her 2-legged family with her.

I have seen a mother eat her entire litter and I have seen a new mother try and kill only her first born until the shock and surprise of the foreign object is replaced and the "mothering" hormones kicks in.

Personally, I would have your female spayed.  Not all females are destined to be mothers.