Hi ! The clinical features you have described of both your children points towards a infection of stomach and intestines, specially from a common source. You have to check the dates of the juices and to note if they were kept open for long. Also the chicken may be a culprit. In summary, you should check the hygienic status of the food they have had in the last one or two days. See that none of them lands up into dehydration
. You have to give them proper antibiotics and nutrition under care of your family physician/paediatrician. So consult either of them. Good luck.