You have got some poisonous creeping buttercup in there; some can look similar to self seeded geranium - if in the least doubt, rip it out. Thankfully they don't root deep and be ripped out pretty easily, especially if you water them beforehand so the ground is moist and the roots come out.
Search your lawn every year once they come up in spring/early summer and pull them up; within a few years you'll be rid of them! they have a habit of making offshoot - follow each offshoot until you have got them all.
Any buttercup is not good news for grazing animals - there seem to be a few in your neighbour's garden. Just keep an eye on any that come up in your lawn. Your piggies won't die from eating just a little bit by accident, but the less you expose them, the better.