We have 2 separate warehouses not by choice but by luck.
When I started. I was doing business out of my garage. Things grew and ended up signing lease at my first warehouse which we out grew in 6 months and ended up a 2nd warehouse in the same complex.
So we decided to do captive bred in smaller and wild caught in bigger.
I have been doing it for 5 years commercially and in 5 years I have never seen ich or velvet in captive bred, but brook and internal parasites, intestinal worms etc. are there which require prazipro treatments.
You are correct some wholesalers also mix captive bred with wild caught livestock which might be the reason for the contamination.