Hundreds of pro-hunting protesters gathered outside the RSPCA's Horsham HQ to demonstrate against its campaign to ban the sport.
More than 300 owners and their dogs marched from fields in Southwater to the charity's new £16 million base.
The protesters say banning hunting would lead many of the estimated 20,000 working dogs being destroyed because they could not all be rehomed.
Richard Meade, 63, a former RSPCA council member and Olympic Equestrian gold medallist, said: "I worry hugely about the animal welfare implications of a ban on hunting with dogs.
"A ban would have dire consequences for the fox species, a large section of the horse population and for many thousands of hounds and working dogs.
"The reality is, many dogs would be destroyed after a hunting ban."
Mr Meade, who was expelled from the RSPCA for his support of the pro-hunting lobby, said the charity was more concerned with spending money on high-profile campaigns rather than animal welfare.
Jonathan Broise, who has a pack of 80 dogs in Petworth, believes licensing hunts would be a better solution that an outright ban.
He said: "It is impossible to rehome hounds to live on their own."
Representatives and staff from hunts across the South East took part in the demonstration.
RSPCA spokeswoman Ann Grain said: "The hounds are their property and they are responsible for those dogs.
"If any of them did need to be rehomed the RSPCA has always said it would help where it could but we would dispute the figures they are bandying around."
John Rolls, RSPCA director of communications, said: "Today's Countryside Alliance protest is no more than a stunt carried out solely for publicity purposes and with little thought for the welfare of the dogs concerned.
"This is the desperate act of an organisation that has lost all the arguments and is clutching at straws.
"We are taken aback by the hypocrisy of these hunts, which admit to shooting 3,000 dogs each year when they are no longer fast enough to catch a fox."
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