Hello, my name is***** and I have over 20 years of experience as a veterinarian. I am sorry to hear that your dogs have diarrhea.
Diarrhea can be due to stress, a change in diet, eating things they should not (especially if they go out unsupervised or are fed lots of table scraps), parasites, inflammatory bowel disease or even a food allergy. In cases where multiple dogs are affected a viral or bacterial infection, parasites or eating something they should not or spoiled food seems most likely.
Since they still feel well otherwise though we can try some things at home to help with diarrhea.
I would not feed any food for 12-24 hours. This should help stop gut spasms and restore normal gut motility.
Small amounts of water given frequently are fine as they need fluids after all that he has lost with diarrhea. You can give pedialyte or clear broth to replace electrolytes too.
Today even with the fast you can start Kao-pectate (kaolin and pectin formulation) at 1ml per pound or 1/2 tablespoon per 7-10 pounds of body weight every 6 to 8 hours. This is quite safe and will coat their irritated gastrointestinal tract as well as absorbing bacterial toxins. You can use it for several days until stools look normal. You can find kao-pectate at the drug store.
If anyone has a tense painful abdomen, continues to have diarrhea with no improvement after being on kao pectate for 24 to 48 hours, becomes very lethargic, begins vomiting or runs a fever greater than 103.5F then that pup really must be seen by a veterinarian as soon as possible. Make sure to take a fresh stool sample with you when you go.
After the food fast start a bland diet of 2/3 boiled white skinless chicken, all fats and juices drained off the meat, mixed with 1/3 boiled, plain white rice. Feed several small meals a day. You might wish to add 1 to 2 tablespoon(s) of canned pumpkin to each meal if you are seeing mucous or blood in the stool as fiber helps soothe an irritated colon.
You can also add probiotics to the bland diet to replace the good bacteria lost with diarrhea. Good brand name products include Fortiflora or Benebac. They can be found online or at pet stores.
Once everyone feels better (no diarrhea for 48 hours) start mixing in regular food very slowly, less bland more regular with each day. It should take a week or so to convert them back.
Ideally you should have their veterinarian check at least a couple fresh stool samples too for parasites as parasite eggs/cysts are shed intermittently and could be part of the trouble. With multiple affected dogs I would be surprised if parasites aren't at least part of the trouble. They may be picked up on the second sample or third test if the first is negative.
Please let me know if you have any further questions.