They were born on June 21, right? So they are one week old today Would their mom-cat still be providing stimulation for them to pass urine and stool? I don't think it's crazy to keep tabs on what they put out. Since you're already measuring how much they take in and watching for growth. You'd be taking further action if they were not stooling, so I'll say it: Yay, kittens! You are eating and ... uhmmm ... pooping!