Use Debrisol (wound spray), it keeps flies off as well. Do you also have Betadine spray? that's also handy for wounds.

If your dog has fleas, bathe him in Malawash, and wash out whole kennel in malawash, use new bedding as well.
No dogs should have a flea problem if the whole kennel has been kept clean and dogs bathed regularly. A lot of big farms use the Confidor product which is like front line, should work.