The full answer
For meat, there is no separate category of “Halal but not Zabiha.”
A cow, chicken, lamb or goat may be an animal Muslims are permitted to eat, but its meat becomes lawful only when the animal has been properly slaughtered.
HMS states that meat from a permissible animal that has not undergone valid Zabiha cannot properly be called Halal.
Answers in the Halal Knowledge Center reflect the standards followed by Halal Monitoring Services (HMS), which operates as part of the Shariah Board of America. HMS certifies only what it checks.