Hopalong, you answered my question on why respond to an old thread.....
In reading over the responses, i felt the need to clarify something.
YES, maggots are often used in the medical field to clean up dead tissue in wounds that are slow to heal...as in a diabetic patient with a foot wound, as one example. Maggots will only eat dead tissue. ONLY. and that is good for cleaning out a nasty wound, and it can be lifesaving....as dead tissue can easily turn into gangarene and result in blood poisoning and death.
HOWEVER, the maggots used in the medical field are bred in sterile labs. They are completely germ free. The ones in these horses' wounds are NOT sterile....nor are the flies that laid them. These flies could have just fed off of a manure pile or a rotting carcass along a road. They should not be allowed to remain in your horse's wound due to the fact that they could be carrying all kinds of nasty microbes. IF they were sterile, they would be doing your horse a favor, but they are NOT sterile...
Any wound with maggots needs to be cleaned out by a vet and the wound debrided. Debrided means that the dead tissue is scaped off. Dead tissue cannot stay in that wound any more than the non sterile maggots can. ONLY a vet should debride a wound. NEVER do it yourself, or attempt to.
I also DO NOT reccomend pouring bleach, diluted or not, into wounds. Bleach is a corrosive, cyto toxic solution....it can and will kill healthy tissue and prevent any cell regrowth.
Call a vet ASAP.