Illinois Law Expands “Pet Custody” Principles Beyond Marriage

Summary: With passage of the Companion Animal Custody Equity Act, Illinois is the first state to empower courts to consider the animal’s well-being in possession disputes regardless of marital status. Unlike traditional “pet custody” laws, which are housed within divorce statutes, Illinois’s new law amends the article of replevin, or property recovery, to explicitly include companion animals—thus moving “pet custody” principles into a broader civil context.

Illinois has become the first state to statutorily apply “pet custody” principles outside of the formal family law context.¹ Effective January 1, 2027, House Bill 4540, or the Companion Animal Custody Equity Act, empowers courts to consider a companion animal’s well-being in possession disputes regardless of the marital status of the parties.

In contrast to similar laws housed in divorce statutes, HB 4540 amends the article of replevin, or property recovery, to explicitly include companion animals. In so doing, it expands legal recognition of companion animal well-being—including factors like their emotional bonds and degree of vulnerability—into a broader civil context. Importantly, it includes special consideration for senior animals that acknowledges their unique psychological and emotional needs.

What Does HB 4540 Do?

HB 4540 empowers courts to consider the well-being of a companion animal in possession disputes regardless of the marital status of the parties. The law provides a list of ten non-exhaustive factors that courts may consider as relevant evidence. Among them are:

• daily caregiving responsibilities;
• emotional bonds between the animal and each party;
• stability of the animal’s living environment;
• age and physical or behavioral vulnerability of the animal;
• and continuity of routine and care.

Notably, the “emotional bonds” factor centers the animal’s experience—the bond between the animal and each party—rather than only focusing on the humans’ bond with the animal. This is an important distinction consistent with the slow expansion of anthropocentric legal frameworks to include the subjective experiences of animals.

Courts may also evaluate ownership documentation. However, proof of legal ownership—historically the dispositive factor in such disputes—“may not be determinative on its own.” This is a significant departure from the strict property analysis that was previously the dominant framework.

In addition to these evidentiary factors, HB 4540 also allows for “temporary possession or caregiving orders, including limited visitation, if necessary to reduce stress or disruption to the companion animal.” [Emphasis added]

Significantly, the new law contains a separate provision for senior animals. For companion animals 10 years of age or older, “courts may give additional consideration to factors including continuity of environment, emotional stability, stress minimization, and maintenance of established routines.”

The senior animals provision reflects the law’s catalyst. HB 4540, also referred to as “Rosie’s Law” in the media, was inspired by a senior dog named Rosie who, following a separation, “was removed from the daily relationship she had known with her primary caregiver for years.” Because they were not married, possession of Rosie was determined using a traditional property analysis without considering factors related to her well-being and caregiving history. Rosie’s former guardian spearheaded the effort to close what she identified as a gap in the law revealed by Rosie’s case.

How Is It Different From Other “Pet Custody” Laws?

In 2017, Illinois became the second state to pass a traditional pet custody law, which is housed within the statutory code governing marriage and applies only to divorcing spouses.² As of 2026, a total of nine states and Washington, D.C., have amended their divorce codes to either require or empower courts to consider the interests of the companion animals in marital possession disputes. Similar bills are pending in other states. These laws acknowledge that companion animals should be treated differently than other marital property such as cars, furniture, and material objects.

With the first having been passed only a decade ago, the word “traditional” is not typically applied to pet custody laws. However, Illinois’s new law uses this developing framework to create a distinct mechanism for courts to make similar determinations in possession disputes involving unmarried parties. The passage of HB 4540 represents a new type of “custody” law and is quietly groundbreaking in its expansion of such principles beyond the family law context—meaning it can apply to possession disputes by unmarried couples, domestic partners, roommates, and other relationships outside of marriage.

Thus, it centers the physical and psychological well-being of companion animals regardless of the marital status of the humans fighting over them. Ironically, but logically given the current legal landscape, it does this by explicitly adding companion animals to the replevin (property recovery) article of the civil procedure code.

Both the 2017 divorce law and HB 4540 are important from an animal protection standpoint, as they transcend the strict property framework historically used to determine legal ownership of companion animals. However, they accomplish this in different ways.

An area where the new law could be stronger would be making it mandatory. While the 2017 pet custody law requires courts to take into account the well-being of the animal, HB 4540 is permissive and merely gives judges the discretion to extend the legal “well-being” standard outside of the marriage context. In addition, the earlier law enables judges to allocate either sole or joint ownership, but the new law only allows for sole ownership.

Why Is It Important?

The factors that courts may now consider are significant because they center the animal’s experience and individuality, broadening the question of “who owns this property?”—the core of replevin—to include the interests of the property themselves. Thus, it expands the jurisprudential understanding of animals as a special kind of property by adding a relational dimension. It accomplishes this without challenging the underlying property framework, which was intentional on the part of lawmakers.

Although situating HB 4540 within the replevin statute could be interpreted as further entrenching companion animals’ legal status as property, this positioning accomplishes something more forward-thinking. By adding legal recognition of animal well-being directly to the statute that deals with property recovery, HB4540 challenges the binary conception of animals’ legal status that juxtaposes property status and legal personhood as incompatible.

As the Animal Legal Defense Fund and others have argued, property status does not preclude animals from obtaining ever stronger rights and protections. Indeed, an entity can be both property and a person. Although often positioned as such, these legal concepts are not mutually exclusive. Rather, they may overlap, as in the oft-cited case of corporations and ships. As the Animal Legal Defense Fund notes:

Personhood is not an all or nothing concept — entities like corporations are legal persons with some but not all legal rights that humans possess, and corporations are also property that can be bought and sold. Obviously, animals can have standing or be legal persons without having identical rights to humans or upending animals’ legal property status.

Illinois’s Companion Animal Custody Equity Act is a small but profound illustration of how animals can receive enhanced recognition both of their species-typical and individual interests while still remaining property.

Progressive Property Theory

In her recent article, “Progressive Property and Animal Law,” Sarah Schindler likewise observes that “defining animals as property does not need to be a dead-end for the expansion of their interests, given that property is a construct that is flexible and broader than its common understanding suggests.”³

Discussing the evolution of progressive property theory over the last decade—and its significance to animal law—she notes that “a progressive view of property decenters the owner and instead focuses on the needs and interests of society more broadly” (p. 670). She argues there is no reason that this broader focus should not include animals. Thus, property law can be “an important tool in creating justice and inclusivity” (p. 671). She concludes:

I do not believe that a property-first (or property-only) approach will necessarily achieve the goals of justice for animals, but I do believe that working within the property framework unless and until animals are viewed as legal persons can further some of these goals (p. 685).

Schindler notes that traditional pet custody laws are an example of progressive property principles in action (even if courts and advocates do not explicitly recognize it as such). The Companion Animal Custody Equity Act further demonstrates the utility of a progressive property framework in advancing the interests of animals. It does this in an intriguing way: by incorporating recognition of companion animals’ psychological and emotional well-being directly into the statute governing property recovery.

Any opinions contained in this article are the personal views of the author. They are not necessarily representative of the opinions or views of the Animal Legal Defense Fund or any clients. This information is presented for informational purposes and does not constitute legal advice.

Further Reading

• Pallotta, N.R. (2017). Alaska legislature becomes first to require consideration of animals’ interests in custody cases. Animal Legal Defense Fund. https://aldf.org/article/alaska-legislature-becomes-first-to-require-consideration-of-animals-interests-in-custody-cases/
• Pallotta, N.R. (2019). Chattel or child? The liminal status of companion animals in society. Social Sciences, 8(5), Article 158. https://www.mdpi.com/2076-0760/8/5/158
• Rosie’s Law Initiative. (2026). The Companion Animal Custody Equity Act (HB 4540). https://rosieslaw.us/
• Schindler, S. (2025). Progressive property and animal law. UC Davis Law Review, 59(2), 657–719. https://lawreview.law.ucdavis.edu/archives/59/2/progressive-property-and-animal-law

References

1. Although “pet custody” is the common colloquial term, these are statutorily defined as possession disputes. Pet custody principles consider the animal’s interests rather than using a strict property analysis to resolve such disputes.
2. This provision pertaining to companion animals was added to the Illinois Marriage and Dissolution of Marriage Act in 2017: “Either party may petition or move for the temporary allocation of sole or joint possession of and responsibility for a companion animal jointly owned by the parties. In issuing an order under this subsection, the court shall take into consideration the well-being of the companion animal.”
3. She further notes: “While a move away from treating animals as property (and toward treating them as legal persons) might seem too radical to some lawmakers, acknowledging how much can be achieved within the bounds of property might be a middle ground that still leads to positive results for the animals. It could also serve as a bridge towards an eventual transition from treating animals as property to legal personhood” (p. 666).