Meanings of whickered in in English

A horse whickered in his stall when Tyrion let the door slam shut.

Rusher whickered in return, stamping one hoof and nodding his head up and down.

Suddenly the Karstark lancers were fighting for control, as their horses rolled their eyes and whickered in dismay.

It whickered in consternation.

'Old Ferox here is as steady as they come, aren't you, boy?' He rubbed the horse's grey muzzle affectionately and the beast whickered in response.