hey there. I got the same problem and fixed it by removing any blocks above the turtle egg. the pigmen's A.I is programmed so that they will only try to "kill" the egg if the space above is free. most farms usually make a roof with slabs so that other mobs dont spawn. if thats your case, try to remove any blocks above the turtle egg. i hope i was able to help 🙂
Leon Laus
hey there. I got the same problem and fixed it by removing any blocks above the turtle egg. the pigmen's A.I is programmed so that they will only try to "kill" the egg if the space above is free. most farms usually make a roof with slabs so that other mobs dont spawn. if thats your case, try to remove any blocks above the turtle egg. i hope i was able to help 🙂