Mouth Brooders

Hello,

I was wondering if anyone here has had experience with breeding mouth brooders. I am considering researching mouth brooding cichlid behaviour and whether or not they ever suck up someone elses fry by mistake (either different species of fry or same species but not theirs)? I realise the chances of this are small as most people would separate their fish into their own breeding tanks but on the off chance has this ever happened to anyone?
Or can you take someone elses fry batch (same species) and add it to the some other cichlids brood?

Thanks