I don’t have isolation facilities

It is worth thinking about whether you could section off a suitable isolation area, using temporary fencing for example.

If this is not possible, use triclabendazole immediately, following it up with one of the fluke treatments which kills adult fluke three weeks later. Beware that, even after treatment, sheep can still shed residual fluke eggs for a few weeks.

Try to avoid putting them on wet ground where mud snails might live.