I wouldn't heptavac and worm at the same time. The first hep dose can really knock them down for 24 hours or so, with them noticeably looking under the weather, so I would either worm first then hep a few days later or the other way round. We are giving 2nd heptavac dose tomorrow, wormed last week and will crovect them in a few days time. They are coming in tonight to make sure they are dry and will stay in until 5-6 hours post crovect treatment. I wormed all our lambs on my own last week, it's the heptavac that needs 2 people I found.