OMG ! THAT's just horrible ! I'm so so sorry - I hate to say this too but it DOES ound like they got into something poisonous - for 2 young dogs to go like that it had to be something they ate .....I know that doesn't help you at all with your grief - but you need to check your home - and your yard too - I've heard horror stories about neighbors throwing things over fences .....
you have my condolences - what a tragedy for your whole family....
