Antimicrobial resistance is a global health threat and because it is often encoded on plasmids, it is crucial to understand the dynamics of plasmid spread and host adaptation. It was shown that IncK plasmids can be divided into two separate lineages named IncK1 and IncK2. IncK2 plasmids are found predominantly in poultry. The relatively high body temperature of chicken influences IncK2 plasmids fitness cost, copy number and stress response in the Escherichia coli host. These data shed a light on IncK2 plasmid’s success and persistence in E. coli of chicken origin. This study analyzed 50 IncK2 carrying isolates of human, poultry, cattle, pig and environmental origin from 10 European countries and Lebanon, as well as 14 publicly available IncK2 plasmid sequences. IncK2 carrying isolates analyzed in this study were sequenced using both Illumina and Nanopore technology. A phylogenetic analysis of all plasmids was performed in order to determine the genetic relatedness of IncK2 plasmids isolated in different countries and from different sources. Additionally, a genome wide association study (GWAS) was performed on annotated sequences to assess if an association exists between specific genetic features and various sources, that could explain the suspected IncK2 plasmid adaptation to the chicken host. The obtained results show that an antitoxin for the Hok/Gef family protein and YdeA protein were predominantly found on plasmids isolated from chicken and therefore are significantly associated with IncK2 from the chicken host. Moreover, protein YffA is significantly associated with IncK2 from human. In combination with prior findings, this study shows that adaptation of plasmids to a chicken host is a complex process that involves both physiological and genetic determinants. Understanding the basis of plasmid adaptation may lead to the development of intervention strategies that reduce the spread of AMR plasmids between different sources.