Hi NN, this business about Jeremy claiming to Muggy that he strangled rats has been covered previously.
One of Jeremy's duties on the B amber farm holdings was keeping a grip on the neverending problem of the rat population.
To do this meant laying down Warfarin, or similar dosage, in the drains or rat-runs. This treatment is continued until such time that there is no take up of the bait.
The joking term of 'strangling' the rats was said in jest, and when translated by Stan Jones, becomes:-
"I can say that Jerry says that he got in practice by strangling rats with his bare hands".