I used to start my poetry lessons in exactly the same way. I used the poem Poetry Jump Up by the brilliant John Agard. I would show the video below (which can be found on YouTube). At first, the children enjoyed watching it, especially the funny moments. After a few weeks, they were joining in with it and anticipating the (slightly!) rude words towards the end. By the end of the term, they knew most of the poem by heart. If I tried to vary the beginning, I would get complaints that they didn’t have Poetry Jump Up. I found this video was suitable for anyone from Year 2 to Year 6. If you have different beginnings to poetry lessons, I would be interested to hear your suggestions. (You will need to double click on this link to watch it.)
Find out more about John Agard here, and listen to him reading another of his poems.