She is hardened against her young ones, as though [they were]
not hers
Hence said to be cruel, ( Lamentations 4:3 ) ; not against the young ones she hatches, for Aelianus F3 reports her as very tender of her young, and exposing herself to danger for the preservation of them; but being a very forgetful creature, having laid its eggs in the sand, where it leaves them, forgets where it has laid them; and finding other eggs sits on them and hatches them, and regards the young as its own, and is hardened against its true and real young, as not belonging to her;
her labour is in vain without fear;
in laying her eggs and leaving them in the dust, without fear of their being crushed and broken, which yet they are, and so her labour is in vain; or her labour in hatching the eggs of others, without any fear or care of their belonging to others, which yet they do, and so she labours in vain.