If the neighbors have encroached one feet of your land and if you have to protect your remaining land also, you may have to file a suit for mandatory injunction against the encroachers to remove the one feet encroachment and to restrain them from interfering in your possession and peaceful enjoyment of your proeprty.
Simultaneously you can cover your property by barbed wire fencing so that the encroachers may not be able to encroach any further.
You may first issue a legal notice to the party to remove the encroachment and deliver possession of the encroached property.
If they fail to respond then you may initiate legal action through court as suggested.