What symptoms are they showing? Why do you think it is dysentery?
If it is diarrhea then mix 1/2 pint of warm water with 1 half tablespoon of glucose, honey and sugar and half a teaspoon of salt. Make certain that they drink thia as they will quickly bcome dehydrated..
Also, unless you have a source of probiotics, get some natural youghurt and put it in the bowl formed at the front of the mouth by the lower beak. That will help them fight any bad bacteria that are causing the symptoms.
Do you have any antibiotics? If so, what have you got or what can you get?