Re YBS. A vet put it to me like this, ybs is comparable to us humans having glandular fever, a high temperature, muscles ache, fatigue etc. The first thing to do is keep them confined to the loft, first and foremost they need to be rested. I personally would then put them on a course of antibiotics (4 in 1) to stop any secondary infection taking hold. All being well you'll see a vast improvement in 4-6 days and have them back on the road in 7-9 days.