I may be misunderstanding what you mean, but it sounds to me not unusual for hogs to be amongst shrubs, etc. during the day – as long as they aren’t out in the open. If we didn’t have hog boxes, they would be spending their time amongst bushes, hedges, etc. When the weather is warm, they don’t necessarily make very substantial nests. But if he was out in the sunshine, that would not be normal – i.e. if he looked as if he was sunbathing – that sort of thing. In that case it is likely he is unwell.
If you are concerned, you should ring BHPS on 01584 890801 and they will be able to give you contact details of your local hog carer/rehabilitator and you can explain in more detail to them and take their advice.