My chicks have been having some really runny poo a lot more lately. Ranging from light brown to a mustardy color. The things I've been doing differently is I added ACV to their water (the wrong kind it turns out. I used the cheap regular stuff and now that I know it's wrong, I'll switch it the the organic "mother" stuff) and I've been giving them watermelon. Which of these two do think is the culprit?