Who would drink more water?

[Carrottom]

Would a stabled horse with hay drink more than a horse in a field of grass?
My boys usually come in during the day, the stables are cool in the morning and gradually heat up after midday so I turn them out about 4ish as there is shade in the field by then. Our water supply is rather low so wondering if they might drink less if I left them out, there is plenty of grass as I can move the fence into ungrazed areas of long grass.
Just wondering if this makes sense, the water will have to be carried in containers to either the field or stables.

 

[JillA]

Normally I would say out, because there is moisture in the grass. But probably not so this year - most grass is more like standing hay

 

[Goldenstar]

I think during this weather I agree with the above .

 

[Carrottom]

This is how I am thinking too. There is a nice breeze to help keep them cool but this is probably a drying breeze too. Thank you.