If a sheep has footrot then maggots aren't such an awful thing, briefly. They clean out the foot before they get down to flesh, so if you find them early then you will have had help to clear up the footrot. Maggots were an ancient treatment used to clean out infected wounds before antibiotics were developed.
As you've discovered, the maggots rapidly crawl up onto the belly when the sheep is lying down, and can go un-noticed there.
A couple of days ago we realised all of our lambs, but no ewes, were being mightily bothered by flies. We rounded them up for Crovecting, and fortunately not one had been struck
![Relief :relief:](https://www.accidentalsmallholder.net/forum/Smileys/default/relief.gif)
It was 6 weeks to the day since the Crovect had been applied previously.
It's just so horribly muggy and perfect fly strike weather.