Kimmy,
Based on the description, they are maggots. The dog attack most likely left small weepy wounds that created the perfect environment for fly larvae (maggots) to grow. I had a similar thing happen to a rooster (possum bite on the tail). My suggestion would be to trim back the remaining feathers around the affected area. This makes it easier to work and helps the area dry. You can use an epsom salts solution to rinse/clean the maggot infested area. Pull off as many of the maggots as you can. Tweezers help greatly. Rinse the area frequently as it will help flush out the maggots. For my rooster I rinsed the area with povidine iodine (available from most pharmacies and grocery stores; it is an antiseptic). This flushed out more maggots. I did this daily until I was confident that the area was healing, but continued to check after that. It was about day 4 before I stopped seeing new maggots. They will continue to hatch for as long as the environment is right for flies to lay eggs. I also applied some SWAT ointment around the affected area to deter flies from laying more eggs. Horse people use SWAT, so look in the horse section of TSC for that. By using iodine rather than an antiseptic ointment, it will allow the area to dry better and therefore be less conducive to maggot growth. Good luck!
