We occasionally receive questions about contamination of hay and dried grass products with foreign material. Typically this is baler twine or similar inorganic material. If this is long or thick enough, it could cause an intestinal obstruction if eaten. However, rabbits may chew on, but rarely eat large amounts of such material. Another concern is organic material, meaning, sadly, parts of an animal carcass.
This may be a wild rodent, bird, or even a rabbit, which has been caught up in the cutting and baling process. In most cases, such small animals, caught up at the height of dry weather, rapidly dry out and, dessicated like this, do not support bacterial growth or prove interesting to flies. Rabbit Viral Haemorrhagic Disease is, however, able to live on organic material for several months, and even dry pieces of a dead rabbit may harbour it. We would therefore suggest that if moist, foul smelling animal material is found in a bale, everything which has come into contact with that item (ie the hay all around it) is disposed of, along with it itself. This includes any wet, smelly or discoloured hay.
If the hay is in a mixed up bag (ie initially baled, then packaged into smaller bags) there is more risk that disease is present throughout the hay, and this should all be disposed of, whereas in a bale, the potentially infected material is likely to be quite discrete. If any dried material is found, the risk is generally much lower, and either that material alone, or surrounding hay that has or may have contacted it, should be discarded. If the animal carcass is that of a rabbit, then it carries a particular risk to pet rabbit of carrying RVHD, and the whole bale or bag should be discarded oronly the visibly uncontaminated bits used for non-rabbit pets only.