Well I don't mean never to dose them, but if they don't need it going in to the shed then consider skipping this one. There will definitely be some animals within the group that do not need dosing if you wanted to try it as an experiment.
The fact that you always used it and it worked fine will, definitely, run out. Every dose you use now is a dose less that will work down the line as resistance will be created. I'm not having a pop at you BTW, it sounds like you have been ticking all the correct boxes, but we are all going to have to change.
Dose and move Was the right thing to do, now it's totally the wrong thing.....we need to put back in non-resistant parasites to the stock so they need to get exposure immediately after dosing. There is very little promotion to the arising issues, but are probably as serious to farmers as antibiotic resistance.
This might help explain it a bit better.....