I have found that my Cichlids will eat any sort of meat i throw in the tank like after dinner if their is any meat scrapes i just chuck a small amount in the tank and they all race up and eat it
and what ever is left the cories will eat so yeah i recon u could use chicken heart the same as cow heart
anouther thing my Cichlids love to eat is small bugsto get that to happen i just leave the light on at night and the lid off tank where my light is and the bugs fly into the light then fall in the tank it fun to watch