Can anybody help me? I don't know what I'm doing wrong with this model. The model does not appear, the normal creeper appear.

creeper.jem

{
"textureSize": [128, 128],
"models": [
{
"part": "body",
"model": creeper_body.jpm,
"attach": false,
"id": "body"
},
{
"part": "head",
"model ...

Is there any solution to this lowering of fps? in the images it´s clear how the models lower the fps a lot.