Good quality hay is one of the best horse feeds, in most cases being only second to fresh grass. In addition to providing nutrition and energy, it is relatively natural (close to the dry grass that horses would naturally eat during the dry part of summer or winter) and provides mental stimulation (unlike concentrated feeds, such as musli).
The main issue with hay is that the quality can vary from very good to very bad, with poor quality hay risking making your horse sick, including potentially fatal illnesses such as colic or laminitis.
The qualities of good hay are:
There are a number of indications of good quality hay. The main factors to consider are hay color, composition, bale texture, smell, and supplier. These are discussed below.
The color of hay is an indication of both the type of hay and the quality. Following are some indications:
Composition and Texture
With good hay, the stems should be relatively short and thin, and easy to bend. Stems which are thick, stiff or brittle are of lower quality. Hay with a higher amount of leaves is more nutritious than hay consisting mainly of stems.
When the bale is opened, it should easily separate at all points. If it clumps or sticks together at any point, or is matted, this is a strong indication of mold or fungus.
The hay should not be dusty. It should not contain stones or earth. A bale which is unusually heavy for its size can indicate the presence of rocks, dirt or excess moisture (the last of which leads to mold and fungus).
If there are any weeds in the hay, ask what weeds were present on the hay field so that you can confirm that none of them are poisonous (be wary of incomplete or vague answers). Be aware that there are some poisonous weeds which horses will avoid on the field but when baled the weeds lose their distinctive smell and appearance so the horses will then eat them. Weeds also make the hay less palatable to horses and may contain irritating items such as burrs or thistles.
The bale should not have any animal parts (e.g. mice, beetles, etc.) and any such bales should be discarded, even if the animal part is confined to only one part, as contaminated bales can make a horse ill or even be fatal.
Hay can be dried or fermented. The advantages of fermented hay is that it can be easier to keep and it tends to have a calming effect on horses (although one could more accurately describe this as a depressing effect). Many stables use fermented hay to make long periods in boxes (rather than paddock and field time) more acceptable to the horses. Some horse dealers feed fermented hay to overly excited horses or horses with behavioral issues in order to calm (depress) the horses and thereby mask the behavioral issues. However, from the perspective of the horses's physical health and vitality, we consider dried hay (provided it is of good quality) to be better than fermented hay. Another point to keep in mind is that if an animal is killed and trapped in a dried bale, normally only a small area of the bale becomes toxic whereas in a fermented bale the toxins spread to a wider area and consequently can be more dangerous.
Hay should not have excessive amounts of carbohydrates, as this can lead to laminitis. Ponies and certain breeds of horses are particularly prone to laminitis, so if you have one of these you need to take special care. Likewise, if you have a horse which has had laminitis before. If your hay supplier cannot tell you the carbohydrate level of the hay, you can make a rough estimate based on where the hay is sourced from and the time of year it was cut. Your local vet specializing in horses can advise you on this point (the relationship between carbohydrate levels and time of cutting depends largely on the local climate patterns, so local advise is required).
Mares in the last 3 months and mares with nursing foals have different nutritional requirements. Discuss with your vet whether a feed supplement is required. Likewise, special care should be take with foals that the food is sufficiently nutritious (otherwise the foal's growth could be permanently stunted) but is not excessively rich (which can lead to bone and other disorders).
A hay bale smells 'grassy' for the first few weeks after baling, with the smell gradually fading so that the bale becomes odorless. Consequently, either a 'grassy' smell or no smell at all is acceptable. However, a moldy or dusty smell (indicating mold or fungus) is absolutely not acceptable.
When buying hay from someone, it is wise to choose 2 or 3 bales at random and inspect them to make sure they meet the above quality requirements. If the outside is acceptable, you should then cut them open and inspect the inside (expect to pay for any cut bales, although if they are obviously bad upon opening you can dispute the payment).
When taking delivery of hay, it is wise to do the above before final acceptance. Since some dealers put the best hay bales on the outside of the load (to give a false good impression), insist on taking the bales from the center of the load. Do not accept delivery of sub-standard hay as both vet bills and your horse's health may give you cause to regret the decision.
Try to buy from a reputable dealer, who is well recommended. Ask the dealer their policy on bad bales (a reputable dealer should assure you that you will get a full refund). Ideally, try to find a seller who sources hay from the same fields every year, who can consequently provide you with hay of consistent quality and nutrition. Some dealers provide a nutritional analysis of their hay (e.g. sugar, protein and moisture levels), which can be useful. If unsure of a hay supplier, it may be worth asking your vet for advise or checking who the best (and most expensive) local professional horse stables use.
Tell the dealer that the hay is intended for horses and ask if it is suitable. Different animals have different requirements for hay, so hay which is suitable for cows or other animals may be unsuitable for horses (and vice versa). A professional dealer should be aware of the different requirements and supply suitable hay accordingly.
When buying fresh hay, special care should be taken that the hay does not have excessive moisture levels as hay which has been baled with excessive moisture is prone to mold, mildew and bacteria. Stacks of hay with moisture levels above 20% can spontaneously ignite, resulting in the hay burning as well as the surrounding building.
Hay should be stored is a dry, dark, rain proof and well ventilated location. It should not be placed directly on the ground or a concrete floor but instead stored on a wooden platform or wooden pallets to prevent condensation on the underside of the bottom row of bales.