It's Fun to Feed the Little Lambs

This is a story of the adventures,
Of three little girls I'm sure you'll agree,
Who have a wonderful time on an island,
Where there's lots of do and see.
They journey by bus and train and boat,
To the shores of old Lerwick Town,
They see lots of creatures you'll like I know,
Dolphins, and lambs with coasts as white as snow.
They also enjoy feeding the hens,
And looking at all the Shetland cattle too,
They like to pat a "Sheltie" dog,
I'm sure you'd like to do that too.
They have pony rides and swim in the sea,
Where they spot seals and otters too,
They watch Grandma sit and milk and cows,
Can you guess what they also love to do?