What type of hay ? Grass ? Oat ? Alfalfa? Blend ?
Grass can have high levels of sugar and look dead and dry and still have a high protien etc. as well as alfalfa . Oat hay looks "straw" like and is very nutritious.
I like to have alfalfa for morning hay , and oat hay for evening hay. And for my pastured (irrigated grazing bermuda) I prefer an oat hay as a balancer.
Only way to tell is to have it Tested.