Mae pori anghyfreithlon wedi cael cryn sylw yn y cyfryngau dros y misoedd diwethaf, a’i ystyr yn syml yw ymddygiad gwrthgymdeithasol gan rai berchenogion anghyfrifol sy’n rhyddhau eu ceffylau ar dir nad oes ganddynt unrhyw hawl i bori arno. Gan fwyaf nid oes modd adnabod perchennog yr anifeiliaid; mae’r anifeiliaid yn ymddangos yn sydyn, yn bwyta’r holl borthiant ar y tir ac yn diflannu’n sydyn, gan adael perchenogion y tir â chostau mawr i drwsio’r difrod a achosir.
Fly-grazing, as the problem has become known, has attracted considerable media coverage over recent months and describes in simple terms the actions of some irresponsible owners who release their horses onto land over which they have no authority to graze. The animals involved are in the main unidentified in terms of ownership, appear suddenly, strip the land of available grazing and disappear as quickly as they appeared leaving land owners with large bills to repair the damage caused.