Animal rights groups have joined the RSPCA's call for greater transparency over the pilot badger cull in England.
The charity said "very little information" had been disclosed about the way the cull was being carried out "despite much questioning".
Defra said independent experts would publish a report after the pilot in Gloucestershire and Somerset ended.
The groups are calling for information about how humane the cull has been and numbers of badgers killed.
Four people were arrested by police inside the Gloucestershire badger cull zone in the early hours of Friday.
They were held on suspicion of aggravated trespass after police responded to reports of horns being blown and individuals straying from a public footpath.
Officers said the four refused to give the arresting officer their details after they were stopped, but a short time later they supplied the information and were released.
About 5,000 badgers are to be shot in a six week-period in Gloucestershire and Somerset in a bid to curb bovine TB.
The pilot began last week but no-one involved will say how many badgers have been shot or killed.
'Ineffective and unscientific'
Joe Duckworth, chief executive at the League Against Cruel Sports, said: "To the anger of many, Defra is still to answer vital questions concerning the methodology of the culls.
"We are particularly dismayed that we have not been provided with any clear information on the assessment of humaneness."
A spokeswoman for Animal Aid added: "I don't think we've had many details at all. They were saying the cull was going well before it had even started.
"We don't know the number of animals killed or how many were monitored for humaneness - a key purpose of the cull is to find out if it's humane."
A spokesman for People for the Ethical Treatment of Animals (Peta) said: "We have every right to know how our tax money is being squandered on this totally ineffective and unscientific slaughter of thousands of British badgers.
"Government ministers need to open their books, as well as their eyes and hearts, and see that the only sustainable long-term solution to preventing the spread of bovine tuberculosis is to attack the root cause of the problem, which is the intensive rearing of cattle in the meat and dairy industries."
Freda Brocks, from Stop the Badger Cull, said they wanted to know the number of rounds fired and number of badgers killed.
She added that they wanted Defra to state how many injured badgers would mean the cull was considered inhumane.
The RSPCA has previously said: "We are very much calling for greater transparency from Defra, especially in terms of culling methods and the accurate assessment of humaneness."
A spokesman for Defra said: "An independent expert board will scrutinise information on the safety, effectiveness and humaneness of the pilots once they have concluded and will publish a report."
The scheme aims to assess if culling can be done effectively, safely and humanely.
There are plans to roll out the scheme more widely in areas which are hotspots for TB in cattle if it is seen as successful.
Anti-cull protesters have vowed to disrupt the shootings.
They want the emphasis to be on vaccines and tighter on-farm and cattle movement measures.