I put a little nipple watering system (screwed one screw-in type into a little empty mustard bottle), and hung it from the top. The chicks (4 days old), figured it out within an hour! I used this predominately until they were about 2 weeks, then set up a 1/2 gallon nipple water jug and 2 nipples (dollar store) hanging inside their grower house, and then a regular waterer outside, that I changed DAILY because they loved to sit on top, and then of course would poo in it!
Today, I just set the chickies (9 weeks) in their big fenced off pen, and set them up a 5 gallon bucket with 4 nipples screwed into the bottom, and hung it from a tree. When I get the big coop finished (2 weeks?), they will move in for roosting in there at night, and then I can move the 5 gallon bucket for inside the coop, and setting up a Little Giant Poultry Waterer for outside (over a little gravel pit with an upturned nursery flat underneath to keep them from making a muddy mess.
https://www.backyardchickens.com/forum/uploads/49101_img_5157.jpg
My little peeps and their nipple waterer at night.
I look forward to NOT having a wet mess to clean up daily inside their coop!
Make sure you use an 11/32 drill bit to make the holes, or you may have leaks! There are other post threads regarding the nipple water system, look them up, they really helped me.