I sympathise. I had a double row under a polythene tunnel cloche and the wind blew it off and wrecked it - its been too wet to venture over the lawn to see if the beans are still there. One of those rigid tunnel cloches might do the trick if you seal it at both ends.

Is there anything else in the vicinity that is drawing rats and mice in or is what you planted the only thing on their dinner plate? Once you have cleaned up your area of any other potential food sources and hiding places, try surrounding your growing area with a fine mesh chicken wire fence (they will chew through almost anything else) at least 5ft high which should go into the ground six inches deep to prevent over and under entry. In my mind, live or lethal traps and poison baits are out of the question if you have children, pets and do not want to risk harming other wildlife in your garden. Remember, with regards to rats and mice, you are dealing with intellegent beings...... Good Luck!

I tend to start mine of in pots and then plant out later in the year.
Due to the cold snap they and others [pigeons, rabbits/squirrels ect] will eat them. putting rat bait down might be a solution.
I seem to remember an old saying about sowing where one of the lines said '1 for the birds'.
welcome to GoY too.