The Color of Good Hay:
Dark Green - This is the color of well-grown alfalfa.
Light-to-Medium Green - The color of well-stored grass hay. The hay was carefully harvested and has a good amount of the nutrients needed.
Bright Lime Green - This usually denotes alfalfa hay that has been treated with propionic acid (a preservative), which will not harm a horse.
The Appearance of Good Hay:
Texture - Stems are shorter and thinner. The stems are easy to bend and are not stiff or brittle.
Stems & Leaves - Hays with a higher amount of leaves are more nutritious than hay which is mostly stems.
Weight - The bale should be light and easy to lift. If it is heavy, it may indicate that it is moldy or that rocks or dirt have been baled into it.
The Color of Bad Hay:
Light/Medium Brown - When the hay has a tint of brown, it contained too much moisture when baled and stored. Brown hay has a musty odor and cakes together. The bale is stiff and the strings have no elasticity.
Dark Brown or Black - The hay was exposed to rain or heavy fog and dew. This hay is very stiff and brittle, and has lost much of its nutrition.
Light Golden Yellow - The hay has been bleached by too much sun, or is aged. Usually only the outer layers become bleached. If the inside of the bale is yellow, most of the valuable nutrients have been lost.
The Appearance of Bad Hay:
Texture - The hay is stiff and brittle and the stems crack easily when bent. The bale may be heavy and/or hard to split into individual flakes.
Dirt & Mold - If the center of the bale appears matted together, and flakes are difficult to separate, it usually indicates dirt and/or mold. Avoid bales that have a gray tint and ones that are dusty when pulled apart.
Infestation - May be infested by rodents, blister beetles or other animals and insects. Always check every bale for this before feeding it to your horse. Discard any bales that you find animal parts in, no matter how small a part it is. Dead animal parts can carry serious diseases that are fatal to horses.
Weeds - If the hay contains a large amount of weeds and/or un-identifiable plants, do not buy it. Weeds may make hay less palatable, and may contain irritating contents such as burrs and thistles. The nutritional content of this type of hay is extremely hard to diagnose.
Other Important Points:
Inspecting Hay - Before purchasing hay from anyone, be sure to inspect a few bales. Buy a couple bales, cut them open and inspect them thoroughly. Check for mold, moisture, dirt, animal parts, insects, color, weeds, texture...and all of the above.
Consistency - Find a reliable dealer in your area that will supply you with hay year-round from the same fields. This will help decrease the liklihood of sickness or colic in horses that are sensitive to feed-switching. It will also help ensure that the nutrition you are giving your horse remains consistent as to not upset his sensitive digestive tract. Problems may arise if you regularly switch hay types, hay fields, and hay quality.
Hiding Bad Bales - Some hay dealers will pull a trick on many customers by hiding the bad bales in the middle of the load, where it is almost impossible to inspect them. They will sometimes put the best-looking bales (the ones you are most likely to inspect) on the outside. To avoid getting stuck with a load of hay like this, be sure to get the dealer's name, address and phone number, and inform him that you expect a refund or replacement for any bale of less quality than the ones you have inspected.
Fist-cut hay - When buying first-cut hay (hay that is the first cut of the year for that field), be sure to check for exessive moisture and weeds. First-cut hay can be the most nutritious if cut and cured properly, however, if it is not cut and cured properly it is likely to have excessive moisture and mold due to spring showers.