If you do /place structure swamp_hut, the fences won't be connected to blocks.
MC-251498
Witch huts don't have connected fences when placed
Open
7
(Unassigned)
Confirmed
Platform
Low
Commands, Structures
/place
22w18a, 1.19 Pre-release 1, 1.19, 1.19.2, 1.19.3, 1.19.4 Pre-release 3, 1.19.4, 1.20.1, 1.20.4, 1.21.7 Release Candidate 2
Retrieved
Can confirm in 1.19.