I don't have any suggestions about the drinking cups, but I would suggest providing one source of plain water (no supplements).
For normal healthy chickens of any age, they do not need supplements in their water. Plain water, plus a complete chicken feed, will provide all the nutrients they...
Those are probably not causing any problems.
Providing grit is good.
I would consider probiotics optional: not harmful, but not helpful enough to notice any real effect.
If the probiotics are in the water, I would make sure they also have a source of plain water (nothing added to it.) The...
22% protein should be safe for all chickens, of all ages.
Higher protein feed is usually more expensive than lower protein feed. So anyone that wants to save a little money, switches to a lower protein feed as soon as they think the chickens can stand it.
The minimum protein level for young...