The three nouns in the “鸡”,“猫”,“狗” 地念 is considered sound expressions (what kind of character doesn’t matter) and 地 indicates adverbial nouns that indicate 'use
“XX 地 verb” = 'withverb with the sound of ~XX'
Examples:
㕵㕵地叫 = barking in the sound of 'guó, guó'
叮叮地響 = making noise of the sound of 'ding, ding'
“鸡”,“猫”,“狗” 地念 = reading with the pronunciations of 'Jī, māo, gǒu'
Similarly 的 can turn a noun into adjectival noun like 隆隆的雷聲, 轟轟的炮火聲