Just weeks after 20,000 pigs died in a fire at a factory farm in Gelderland, ‘hundreds’ of pigs have died in a blaze in two barns in Agelo in Overijssel.

At first, the fire brigade said nearly 8,000 pigs had died but this was later revised down after the farmer said ‘several hundred’ pigs were in the barns at the time. A few animals are known to have escaped but the actual death toll remains unclear.

The cause of the fire, which broke out shortly before midnight, is unknown. The barns were built in 2011 and the fire spread quickly from one to the other.

In total, some 50 firemen were involved in tackling the blaze.

Animal welfare lobby group Wakker Dier keeps a running tally of factory farm fire deaths which shows some 200,000 animals have been killed so far this year. That means 2017 is likely to be the worst year for factory farm fires since 2011, when 319,000 pigs and chickens were killed.

Although higher safety standards were introduced in 2014, many older barns are still very unsafe, the organisation says. In addition, new barns do not have to have proper sprinkler systems or smoke alarms.

The pro-animal PvdD introduced a motion to parliament at the beginning of July calling for better fire safety at factory farms, but it failed to win enough support. The three Christian parties and two Liberal parties D66 and VVD voted against the measure.