To ensure the sustainability of chicken and rabbit production, some nutritionally practical strategies must be developed. Recently, chicken and rabbit farms have faced feed shortages due to the impact of climate change, high competition among livestock species, and war conditions. The present article aims to provide an overview of previous studies on the potential of using some plant and animal products as nutraceutical alternatives and feed additives in chicken and rabbit diets, separately or in combination, to act as natural growth promoters, antioxidants, anti-inflammatory, and antimicrobial agents, and immunostimulants. From the results, some unconventional plant and animal products can be successfully used as dietary supplements and substitutes in poultry and rabbit farms to improve animal growth, health, and reproduction. These products are rich in minerals, vitamins, enzymes, organic acids, flavonoids, and phenolic acids. These active substances benefit the animal's digestive tract in different ways, including activating the digestive enzymes, maintaining microbial balance, and promoting vitamin synthesis.