* Genetics: Fancy mice are bred for specific physical traits, often involving genetic mutations. While they can still breed with common mice, the offspring might inherit undesired traits or health problems.
* Health: Fancy mice can have health issues related to their specific breed. Mixing them with common mice might introduce diseases or health problems common to common mice that fancy mice are not as well equipped to handle.
* Temperament: Fancy mice and common mice can have different temperaments and social behaviors. A fancy mouse might be less assertive than a common mouse, leading to dominance issues and potentially aggression.
Exceptions:
* Responsible breeders: Some breeders might selectively mix fancy and common mice for specific purposes, but this is usually done with careful planning and knowledge of the genetics involved.
* Specific breeds: Some fancy breeds are known to be more closely related to common mice than others.
If you're considering getting mice, it's best to stick to either fancy mice or common mice. Choose based on your preferences and research the specific breed's health and temperament needs.
Remember: Always research and carefully plan before bringing any animal into your home!