I have 7 chicks that were hatched on 7/9 and been with me since 7/10 and they all seem healthy and are eating, drinking, scratching at litter - but some of them have really watery (and stinky!) poop. They are in a large brooder with a heat lamp, I change the water several times a day, have completely changed the litter 2 times, I scoop out poopy clumps of litter every so often. They eat medicated chick starter. Should I worry? Is there anything I can do to help? Since they are so young, I don;t think I should feed them anything else, right?