One message, from Mal Mckee, said: "Mate, sorry to hear the news. Get well soon. Bones heal, pain is [temporary], glory is forever."
Later yesterday Mr Bull posted another message: "Thank you everyone for your kind words and support. Drugged up & a bit not with it today."
Mr Bull, of Whenuapai, is a well-known face in skydiving circles with more than 30 years' experience in parachuting.
He has represented New Zealand a number of times.
Last month he was part of a group of skydivers who won a gold medal at the New Zealand Parachuting Championships.
After the win, he told the Nor-West News newspaper: "You're in charge of your own destiny as soon as you pop out. You can't ring up and say, 'Excuse me, I need a bit of help."'