Pliny the Elder [1st century CE] (Natural History, Book 8, 72): The lambs at the first birth are smaller. They all couple from the setting of Arcturus, that is May 13th, to the setting of Aquila, July 23rd; they carry their lambs 150 days. Lambs conceived after the date mentioned are weak; in old days those born later were called cordi. Many people prefer winter lambs to spring ones, holding that it is more important for them to be well-established before midsummer than before midwinter, and that this animal alone is advantageously born in winter. It is inbred in the ram to despise lambs as mates and to desire maturity in sheep... They say that male lambs are got when a north wind is blowing and female when a south... - [Rackham translation]

Saint Ambrose [4th century CE] (Hexameron, Book 6, chapter 4.25): What animal is more innocent than the lamb? We are accustomed to make an analogy between lambs and our own little children. It often happens that in a large flock a lamb decides to wander over the whole sheepfold, roaming in search of his mother. When she on her part is unable to find her lamb, she attempts to discover his whereabouts by bleating frequently. By this means she hopes to cause him to give an answering cry whereby he could direct back 'his truant footsteps. Although he has wound his way among thousands of sheep, he still recognizes the voice of his parent. He hastens to his mother and finds his way to the familiar sources of his mother's milk. Notwithstanding the lamb's eager desire for milk, he passes by other udders heavy with milk. These udders, in fact, may overflow with milk, yet he persists in searching for his mother. The depleted store of his mother's udders means just full abundance. She, too, can distinguish her offspring among the many thousands of lambs. In outward appearance they are the same. One can find no differences in the sound of their bleating. The mother picks out her own progeny from the rest of the flock. She recognizes her brood by the sole testimony of parental love. Whereas the shepherd may err in making his selection, the lamb cannot make a mistake in recognizing his mother. The shepherd is deceived by appearances, but a sheep is guided by natural affection. To all appearances, each one has the same odor, yet nature provides for them the power of distinguishing a scent which their own progeny, by I know not what peculiar potency, alone gives forth. - [Savage translation, 1961]

Isidore of Seville [7th century CE] (Etymologies, Book 12, 1:12): Although the Greeks name the lamb [agnus] from “holy” as if it were sacred, Latin speakers think that it has this name because it recognizes [agnoscere] its mother before other animals, to the extent that even if it has strayed within a large herd, it immediately recognizes the voice of its parent by its bleat. - [Barney, Lewis, et. al. translation]

Bartholomaeus Anglicus [13th century CE] (Liber de proprietatibus rerum, Book18.4): The Lambe is called Agnus, & hath that name of a name of Gréeke, as it were milde as Isidore saith. For among all the beasts of the earth, the Lambe is most innocent, soft and milde, for he nothing grieveth nor hurteth, neither with téeth, nor with horne, nor with clawes: and all thing that is in the Lambe is good & profitable, for the flesh is good to meate, and skin to divers vse, and woo• to cloathing, and the dirte to lande, and clawes and hornes to medicine, as Isidore saith lib. 7. Latines suppose, that this nown Agnus commeth of Agnoscendo, knowing: for passing all other beastes, the Lambe knoweth his owne dam, insomuch, that if she bleate among manye shéepe in a flocke, anone by bleating he knoweth the voyce of his owne dam. Avicen[na] and Aristotle meane, that some Lambes be yened in springing time, and some in harvest time, and some in winter: but those that be yened in springing time, be more huge and great of body, & more stronger of bodye, then those which be yened in harvest and in winter. But in some countries and lands many men set winter Lambes, afore Lambes of springing time, and meane, that onely these beasts be profitably yened in winter time, as Plin[y]. saith li. 8. ca. 47. and ther it is said, that Lambes which be conceived in the Northerne winde, be better than those that be conceived in the southern wind, for then males be gendered and conceived. And Lambes have such coulour in flesh and in wooll, as the Ramme & the Eaw have colour in veines of ye tonge, for if the veynes be white, the Lambes be white: and if the veynes be blacke, the Lambes be blacke; and if they bée speckeled, the Lambes be speckeled. In sucking time the Lambe bendeth his knées, and for the dam should give the more milke, he thrnsteth and pusheth at the udder of his dam, and beséecheth the dam with bleating, and sawneth with his taile when he hath found his dam, and beareth up the head, and sucketh never but first it areareth up the head, & hath small wooll and crispe, and manye maner wise folded in it selfe. Cold grieveth Lambes, and namely in raine wether, and be glad and ioyfull of the company of folke, and he cleing and forie, & dreadeth full sore, when they be alone. The Lamb hoppeth & leapeth before the flock, & plaieth, & dreadeth ful sore when he séeth the Woolfe, and flyeth sodainlye away: but anone he is astonied for dread and stinteth sodaynly, and dare flye no farther, and prayeth to be spared, not with bleating, but with a simple chéere when he is taken of his enemie. Also when Butchers bind him fast, he defendeth him not with téeth, neyther with horne, and if he be spoyled either of his fell or of his skinne, he is still an innocent and an harmlesse beast, and whether he be lead to Pasture or to death, hée grudgeth not, nor prauncheth not, but is obedient and méeke, as Plinius sayeth. It is perill to leave Lambes alone, for they die soone if ther fal any strong thunder. For the Lambe hath kindly a féeble head, and therefore the remedy is to bring them together, and leite them goe together, that they may be the bolder because of companye, and the more hardy. - [Batman]