A younghen, especially one less than a year old. (defdate)
1646, (w), Pseudodoxia Epidemica, I.11:
They died not because the Pullets would not feed: but because the Devil foresaw their death, he contrived that abstinence in them.
1749, (w), Tom Jones, Folio Society 1973, p. 588:
The dinner-hour being arrived, Black George carried her up a pullet, the squire himself ... attending the door.
1891, (w), In the "Stranger Peoples" Country'', Nebraska 2005, p. 187:
he recommended that the patient ... should be fed with chicken broth, and suggested that as all the poultry had gone to roost, Maggie would find a fat young pullet an easy capture.
1928, (w), Memoirs of a Fox-Hunting Man, Penguin 2013, p. 195:
The writer complained that a fox had been the night before and killed three more of his pullets….