Hi Lauren, welcome to the forum and to being a chook carer. What's your specific concern, that they aren't eating/drinking enough, or too much, or are you trying to work out cost? I just make plenty of both available and leave it to my girls to help themselves. That seems to work well. If anybody shows any signs of being unwell, then I'd worry. I have two groups, a group of 5 "big" girls, and some little ones. The big girls get through a bucket feeder of crumble every couple of weeks-ish (they seem to get through quite a bit of it). Their waterers are 15 litres, they get filled every week, but the big girls free range as well, so they drink from other receptacles around and about the place.
Sorry, I haven't really answered your question, I suppose my advice is just to give them plenty and not worry.