I am glad you are sceptical of giving them all these meds, I would be too. I never understood why vets do a fecal, and then even though it is negative for parasites they still give a dewormer. Sounds like they are just trying to maximize profits. And antibiotics when he sees no sign of infection really seems like overkill. Why did he suggest you take them off the canned food? Did you change their diet or are they on the same food they were on before you got them?