Cooperative membership and livelihood diversification have been observed to influence households’ economic situations, while little is known about their interplays as a matter of mutual exclusivity when they both occur. This study was hence conducted to investigate the level of cooperative performance and how cooperative membership influences livelihood diversification alongside some other imperative hypothesized determinant factors, using primary data collected from 210 poultry farm holders in a multistage sampling process and analyzed with econometric, parametric, and nonparametric analytical estimators at 95 % confidence interval. Results showed that the majority of the cooperator respondents are satisfied with access to loans (72.38%), Loan repayment (67.62%), transportation (68.10%), marketing (67.14%), training (69.5%), patronage (70%), and Political interference (69.05%) while a relatively large proportion of the respondents (59.04%) are diversified, while a majority (89.52%) of this diversified category secondarily diversifies into non-farming activities. Also, the proportion of cooperator-diversified poultry farming households (59.41) narrowly exceeded the non-cooperator category (58.72); hence, further econometric analyses conducted showed that gender of household head, level of formal education, primary occupation, primary labour source, and cooperative membership negatively influenced livelihood diversification, but otherwise for multidimensional poverty, all significant at P?0.1, P?0.5%, P?0.01%, P?0.01%, P?0.01%, and P?0.1% probability levels accordingly. Econometric analyses of empirical data revealed that multidimensional well-being significantly increased livelihood diversification, which is offset by an increased level of formal education, cooperative membership, male-headed households, and dependence on family labour; hence, effective cooperative management be further upheld so as to maintain and or further improve the current cooperative performance level in order to cushion credit access constraints confronting agricultural activities. Furthermore, cooperative membership was found to negatively correlate with multidimensional poverty; hence, cooperative membership should be encouraged owing to the way it influences livelihood diversification to improve multidimensional welfare rating. Also, well-trained labour should be employed in order to increase managerial efficiency.