A word in the Qenya Lexicon of the 1910s glossed “chicken”, apparently a diminutive of ᴱQ. poroke “barn fowl” (QL/75), though what the larger domesticated bard birds might have been isn’t clear. It was followed by an unglossed form ᴱQ. porokoi.
Early Quenya
poroke
noun. barn fowl, hen
porokelle
noun. chicken
The word ᴱQ. poroke “barn fowl” appeared in the Qenya Lexicon of the 1910s, along with a second gloss “hen” that was deleted (QL/75). In Early Qenya Word-lists of the 1920s, Tolkien glossed ᴱQ. poroke as “hen” (PE16/132). In Common Eldarin: Noun Structure from the early 1950s, Tolkien had primitive words ✶porokĭ “fowl” and ✶porokē “hen” (PE21/82). Finally, primitive onomatopoetic roots √porok or √korok “hen” appeared in marginal notes from the late 1960s (VT47/36).
Neo-Quenya: Given the above, I would retain ᴺQ. porocë for purposes of Neo-Quenya, usable both for chickens in general as well as hens, much as the default gender of the English word “chicken” is female rather than male. For a specifically female chicken, however, I would use ᴺQ. holyë “hen”. The word porocë “fowl” might also apply to domesticated birds in general.