My flock is currently getting a round of Corid, which I have had to do in the past. This time, one of hens is not drinking on her own. I've given her doses by syringe, per @casportpony 's great reference thread. It states to drench dose for 1-3 days. Why is it only 1-3 days, when the corid water mix is a 5 day treatment for severe outbreak? I'm not questioning it, just curious as to why that's the case.