Check out the command that will summon a mob that drops any item in Minecraft.
You can use any mob and any tag.
And you can define a lore, name, and drop chance for the item.
This command changed in some versions, so test a bit, but here are the commands below:
Version 1.21.5+ and 26+
summon chicken ~ ~1 ~ {Tags:["iron_chicken"],CanPickUpLoot:0b,equipment:{mainhand:{id:"minecraft:iron_ingot",count:2,components:{"minecraft:custom_name":"Item Name","minecraft:lore":['Item Lore']}}},drop_chances:{mainhand:1.0}}
Version 1.21.1+ to 1.21.4
summon chicken ~ ~1 ~ {CanPickUpLoot:0b,Tags:["iron_chicken"],HandItems:[{id:"minecraft:iron_ingot",Count:2b,components:{"minecraft:custom_name":'{"text":"Item Name"}',"minecraft:lore":['{"text":"Item Lore"}']}}],HandDropChances:[1.0f]}
Version 1.20.4 and earlier
summon chicken ~ ~1 ~ {Tags:["iron_chicken"],CanPickUpLoot:0b,equipment:{mainhand:{id:"minecraft:iron_ingot",count:2,components:{"minecraft:custom_name":"Item Name","minecraft:lore":['Item Lore']}}},drop_chances:{mainhand:1.0}}