I have two new stray kittens for about 5 days. They look about 4 weeks old but not for sure yet. All they do is cry. We started off giving them kitten milk but they quickly moved to soft kitten food. We try to give them attention, playing with them, talk to them, snuggle them, use laser lights, roam around the house, put them in a crib, but nothing works. They cry all day & all night long & it's becoming stressful. They puked the 3rd night, & one just took a poop right in front of us although previously used a litter box. Any advice on what to do??