Hi, I'm Dr Steve. From what you are describing, your goats may have a skin infection. I see you are offline but I wil try to give you some ideas to try
Hair loss by itself can be caused by several things. When more than one animal in a herd is having hair loss or skin problems, it tends to be an infection or something else that can spread like parasites.
Lice are a very common external parasite that can cause irritation to a goat and they will scratch or rub or lick to relieve the itching and irritation. When this occurs, especially if they lick, they can make their skin too moist and this allows bacteria that are present in low numbers on dry skin to multiply in the wet skin and cause the infection. The fact that they have red and raw looking skin sounds consistent with a bacterial infection.
Iodine may help reduce the bacteria and help with the infection, but often it takes injectable antibiotics to completely get rid of a skin infection. The antibiotic that I have had the best results with is called excenel and is available from your vet. Unfortunately this is not an over the counter medicine. It has worked very well for me.
Once you have addressed the skin infection, you also have to see if there are any external parasites like lice that are causing the initial problem. Lice are tiny, but can be seen with the naked eye if you look very carefully and look with the goat in strong sunlight or use a flashlight. The lice are amber to tan color and look almost like tiny seeds but they move. If you can't see any lice, then look for lice eggs. THese are called nits and are glued to an individual hair shaft near the base or about half way up the hair. They will look like a tiny bump on the hair. There will likely be many eggs if there are lice. If you find evidence of lice on even one goat then they all will likely have them .
Lice can be killed with injectable ivermectin at label dose for cattle.
Fleas and mange are two other possibilities, but both are very uncommon and fleas will be black and very fast. If you see a dark brown or black bug running in the skin as you look through the hair, it is likely a flea. I have neer seen fleas on a goat , but i suppose it is possible.
Mange usually causes actual sores and even scabs, rather than generalized redness and the nly way to know if mange is present is to have skin scrapings done by your vet and then look at them under a microscope.
If you don't have access to a vet and can not get the excenel, another product that I havae used for skin infections is called Vetericyn. It helps to disinfect and flush bacteria off the skin and promotes healing by increasing oxygen flow to the tissues, THis is a spray and may be found in farm and pet stores. This , in my experience isn't as good as excenel but may be better than iodine.
I hope this has helped. If it has would you please rate my answer so I may get credit for my answer. I will continue to check back throughout the evening to see if you have more questions. Thanks for using just answers and good luck.