It is starting to get hot, yes, even here in the foothills of the Northern Colorado Rockies. The horses are sweating more, drinking more and eating more salt.
Horses should have access to salt at all times. I provide each of my horses with two salt blocks. One is a plain white salt block that is simply table salt; sodium chloride. The other is a calcium/phosphorus trace mineral salt block. It is sometimes called a 12:12 block because it contains 12% calcium and 12% phosphorus or an equal ratio of calcium to phosphorus, which is good for most adult horses. Each of my horses shows a preference for one block or the other but all choose different blocks at different times.