Feral kittens "alone" for two days?

Contact a rescue shelter that has a no kill policy and make sure you find out this or it's probable they'd be euthanized. Call the Humane Society, the one in our area has a strict no kill policy where as or city's animal control has a 72 hour kill policy. There's plenty of mama cats that are willing to adopt and nurse another cat's kittens. Make sure they are kept warm and I'd seriously worry about dehydration. Mama cat can be rescued at a later date. But at this stage they require mamas milk to meet their nutritional needs.