The original poem is rarely read these days because it was written in a Scottish dialect contemporary speakers of English don't understand. What follows below is a quite good interpolation by Gregory Marton:

Small, sleek, cowering, timorous beast,
Oh, what panic is in your breast!
You need not start away so hasty
With a hurrying scamper!
I would be loath to run and chase you,
With a murderous spade!
                        
I'm truly sorry that Man's dominion
Has broken Nature's social union,
And justifies that ill opinion
Which makes you startle
At me – your poor, earth-born companion
And fellow mortal!
                        
I doubt not that you may steal;
So what?  Poor beastie, you must live!
An odd ear from twenty four sheaves of corn
is a small request:
I'll get a blessing with the rest,
And never miss it!
                        
Your tiny housie, too, is in ruin!
Its feeble walls the winds are strewing!
And nothing now, from which to build a new one
Of foliage green!
And bleak December's winds ensuing
Both bitter and keen!
                        
You saw the fields laid bare and wasted
And weary Winter coming fast,
And cozy here, beneath the blast,
You thought to dwell.
Until crash!  the cruel plow passed
Right through your cell.
                        
That tiny heap of leaves and stubble
Has cost you many a weary nibble!
Now you are turned out for your trouble
Without house or home,
To endure the Winter's sleety dribble,
and frosty cold.
                        
But Mousie, you are not alone
In proving that foresight may be vain:
The best laid plans of mice and men
often go awry,
And leave us nothing but grief and pain
Instead of promised joy!
                        
Still, you are blessed, compared with me!
Only this moment touches you:
But oh!  I backward cast my eye
On prospects turned to sadness!
And though forward I cannot see,
I guess and fear!

– Robert Burns