I did have medication on hand ~ have just ordered more as I have just about used up what I had on hand. Yes, I have been thinking the same thing. This lot of Vorwerks seem to be thriving. They are older though, close to POL. The older birds of this lot all seem to be ok too. Our weather has been rather extreme: hot & muggy to quite cool in a matter of hours [temp swing of 5+ degrees] so I'm thinking a bit of extra stress hasn't helped. either.I'm sorry to read this Ribh.
Late advice.
Get Amprolium, Permethrin, Chlorhexedine, a vitamin and mineral booster.
I think I would also look for another beeder Ribh. Losing the Vorwerks so quickly which are noted for being reasonably hardy, plus the chick problems you've had makes me think that your breeder doesn't know what he/she is doing.
My view with chicks is get them outside as quickly as possible. Outside is where they are going to live and being outside early helps them build up some tolerance to the local pathogens.
It was a problem here when I arrived. They kept the chicks inside until they were fully feathered. When they let them out a lot died.
I think while your run and coops are great that you have too many chickens for the available space. Just an observation. The 10 square metres rule one often reads is imo about half of what the minimum should be.
Ideally, all prospective chicken keepers should equip themselves with the basic medications before they get chickens. I realise this rarely happens but when a chicken falls ill, you need the stuff there and then, not when amazon or whatever manage to deliver it.
Yes, the run is too small but they are free ranging @ present & that doesn't look like changing any time soon. If they were going to be permanently confined I wouldn't have so many birds but they have the whole yard ~ about 1/2 an acre & the Campines also occasionally explore the hill so space wise there's over an acre of available space. Do you still think that's too small?