[cypher]

I've always found the classic bottles the most reliable & not had problems, what makes you think Hamlet isn't getting any water out?
It can be hard to tell if they are getting any or not but as long as the bottle works ok he should manage.
Does the water come out when you rub a finger over the spout?
I always give mine a good shake after filling to make sure the water is flowing properly.
How about the height of the bottle? Can he reach it without having to stretch if it's too high or drink in an uncomfortable position if it's too low.

If you only have one bottle each it's always worth keeping at least one spare each just in case something does go wrong.