hay suppliers are quite variable with the the description of their hay. It sounds like both suppliers have primarily Timothy fields but both have other grasses mixed in. The 1st being orchard grass the second a mixture to broad to classify so the name "mixed" grass. Probably will not be a problem at all since the primary on both is Timothy so basically the same..although quality is a whole other issue.
The ?? About amnt..it is a self care facility..are your 3 isolated in their own area? There is a lot of waist with rounds..I suggest a keeper that surrounds the bale & keeps them from walking on it, voiding on it. A lg round lasts my 6 about 2 weeks but they are also grained. Not sure what area you are in but if it is part of the drought this year I would get plenty of hay if its available now because the cost is exponentially rising by the day..and that might be why your old barn is hanging on to it.
Horsepower: the extraordinary capacity of a horse to elevate the human spirit!
My castle is my barn ;)