They probably are. If you haven't yet, observe them and wait to see at least one take a drink.
To be sure everything's alright, change the water daily. You may try adding another container too, just in case something is off about the one you're using now.
okay, that makes sense... I noticed that the water ring kept getting dirt in it so I raised the water bucket. That is when I noticed that the water level didn't seem to be going down. Maybe the hens were scratching dirt up. Yes, I have three different water areas and watch to make sure the water stays clean. They may prefer the dirty water as well. I will keep an eye and see if that is the pattern.If you are offering them clean water all the time you are doing what you are supposed to. If it is there they will drink it. Yours have shown they know how. How long has this been going on?
Mine prefer to not drink from the clean water. If there is water pooled on the ground they seem to prefer that. If that water on the ground is clear they are likely to scratch and stomp in it until it gets muddy. Do they have another water source?
You still need to keep the water you offer clean. If it gets dirty it can become a breeding ground for disease. If mosquitoes can get to it you can be breeding mosquitoes. Even if it looks clean, I dump mine every two days and totally refill to stop mosquitoes.