Hi Tata
Dogs are better off not being bathed unless there's a really good reason. Even doggie shampoo washes the natural oils out of their skin and disrupts the natural balance of skin flora/fauna. Has she just finished her season? that might have left her a bit run-down. Have you tried front-line - we had terrible trouble with ticks before, but front-line totally works and isn't toxic. Give your breeder a call, I'm sure they'd be happy to advise.
Are you saying they're eating the pooh from the cat litter tray? I've certainly known dogs that would do that. If you have the patience you could train the dogs not to, otherwise you just have to physically keep the dogs away from the litter tray - could you put the tray up off the floor?