Mutant Ninja Tomato Plants

This morning, as I was outside feeding the chickens and moving their run around the garden, I noticed what I thought were some very large weeds. Now this is not entirely unexpected as my garden is sort of overgrown again. I haven't really had time to mow the lawn in the last few weeks because I have been sewing like a maniac to keep up with the market stall. On closer inspection, it turned out that the "weeds" were not weeds at all, they were tomato plants. Three of them in fact and the only way I can think of them having appeared there is that the seeds must have been eaten my the chickens, who have a particular fondness for tomatoes and when the seeds had been pooped out, they have managed to germinate and grow into fine healthy plants!! They even have flowers on. I am totally amazed because the tomato plants I have been growing all summer are now almost finished but these wild, mutant ninja plants are flourishing. 

If you look closely, you can just see the flowers on this next picture ..... amazing!

The question now, is, what do I do with them? Is it possible to dig them up and keep on growing them or will they not produce anything because it's the wrong time of year? Have any of you had anything like this happen before? I have heard of people having rogue potato plants growing from a spud that has not been dug up and of course apple trees sprouting up from discarded apple cores but has anyone ever had tomato plants growing in weird and wonderful places???