Hi, for those who are following this thread I'd like to bring it to a close
We took a new stool sample to the lab yesterday and the results are in: "negative for ova / oocysts"
That means they could find nothing bad in the poo!
When you collect the fresh poo in the morning, you can't be sure to get poo from all your chickens but you get a good mix. In general if there is something affecting your chickens they are all affected. It's not an exact science, you could have a single sick bird and not collect their poo by accident.
Let's recap:
1) Routine stool sample check uncovered tapeworm and capillary worm infection. The flock looked healthy and their poo looked healthy to the naked eye but under a microscope worm eggs could be found.
2) Treatment with Valbazen appeared to have cured the problem (with another stool sampling) but there was a mild case of cocci detected. This could be the result of the "good gut bacteria" being depleted along with the bad as a result of medication.
3) Instead of further medication treatment, we opted for human yogurt with "good gut bacteria" along with corn and other treats. The chickens now have a clean bill of health.