pooping next door

Hey guys me again....after some much needed advice. Our neighbour approached my husband this morning complaining that one of our cats has been pooping in her front yard. I cannot say 100% that its our cats (flik a torti and cleo a tabby...both spayed and both 2 years old) there are other cats around..so cant say its ours for sure. Anyway...is there any recommendations to help stop them...if it is them...from pooping in her yard. I am home nearly all day, most days so they come in and out as they please and have free reign of their litter box's...any ideas??

The only way to be certain is to keep your cats inside.  Your neighbor can get repellents to put her their yard/garden to try and keep cats away, but once a cat starts going in a certain place, it often returns to the same place over and over.  I would look into one of the repellents and see if your neighbor would use it.  Otherwise you will need to keep your cats inside or build them an enclosure for outside use.