Hi LeytonGabriel
Your best bet re. research might be to contact the Hedgehog Officer at PTES – email address below. Alternatively BHPS may be able to help you can contact them via their logo at the top of the page.
I seem to have plenty of earthworms here – I quite often capture hogs, on video, pulling them out of the ground on the night cams. Although I have also seen that rats (when they are around) seem to have an even better earthworm extracting technique than the hogs! So, sadly rats also are competing with hogs in that respect.
Let us know what you find out.
Good luck.
