I’d say have Chip leave, realising he’s not welcome in the family anymore, and goes off on his own.
Dad goes off to find more food, and just doesn’t return. Mum doesn’t immediately thinks anythings wrong and just eats the food supply to keep her new babies well-fed. It isn’t until she notices that the supply hasn’t been replenished that she realises her mate hasn’t come back, and now she doesn’t have the time or the knowledge to find more herself.
One by one her new babies die of starvation, until they’re all gone. With only Chip left, she tries to find her ‘lastesh babbeh’, only to see that he’s long gone and she doesn’t know when or where he went. The last we see of mum is her shivering among her dead foals as the snow begins to fall.
As for Chip… he found food, a healthy loaf of bread thrown away. But in his excitement, he ate the bread too fast and it got lodged in his throat, choking the poor bastard to death just a couple blocks from his home.