READ OUT LOUD. Choose which marked text you prefer to practice with - macrons in verse form, or macrons in prose order, or accent marks in prose order, or focusing on the meter. You will find materials for all of these options below. :-)
VERSE MACRONS. Here is the verse text with macrons:
Pelle Leōnīnā quia sē vēlārat Asellus,

Dēceptī speciē crēdēbant esse Leōnem,

At prōdunt Asinum longae spectantibus aurēs,

Agnitus unde gravēs pistrīnī ferre labōrēs

Praebeat indignīs ut quondam tempus honōrēs

Arroget ut vānam sibi stulta superbia laudem,

PROSE MACRONS. Here is the same text with macrons written out in prose word order:
Quia Asellus pelle Leōnīnā sē vēlārat, hāc fraude hominēs et ferae pariter pavent. speciē dēceptī crēdēbant esse Leōnem, haec rēs timōre gravī digna vīsa fuit. at aurēs longae spectantibus prōdunt Asinum, quī mōre tālī superbus stolidē erat. unde agnitus cogitur pistrīnī labōrēs gravēs ferre, facta proterva hanc poenam movent. ut tempus quondam honōrēs indignīs praebeat subitō hīs dēdecus, quod fuit ante, redit. ut superbia stulta laudem vānam sibi arroget, fraude patente, laus ea tamen crīmen erit.
STRESS (ACCENT) MARKS. Here is the prose text with accents, plus some color-coding for the words of three or more syllables (blue: penultimate stress; red: antepenultimate stress):
Quia Aséllus pelle Leonína se velárat, hac fraude hómines et ferae páriter pavent. Spécie decépti credébant esse Leónem, haec res timóre gravi digna visa fuit. At aures longae spectántibus produnt Ásinum, qui more tali supérbus stólide erat. Unde ágnitus cógitur pistríni labóres graves ferre, facta protérva hanc poenam movent. Ut tempus quondam honóres indígnis praébeat súbito his dédecus, quod fuit ante, redit. Ut supérbia stulta laudem vanam sibi árroget, fraude paténte, laus ea tamen crimen erit.
ELEGIAC COUPLET METER. Below I have used an interpunct dot · to indicate the metrical elements in each line, and a double line || to indicate the hemistichs of the pentameter line.
Pelle Le·ōnī·nā quia· sē vē·lārat A·sellus,

Dēcep·tī speci·ē crē·dēbant ·esse Le·ōnem,

At prō·dunt Asi·num lon·gae spec·tantibus· aurēs,

Agnitus ·unde gra·vēs pis·trīnī ·ferre la·bōrēs

Praebeat· indig·nīs ut· quondam ·tempus ho·nōrēs

Arroget ·ut vā·nam sibi ·stulta su·perbia· laudem,

IMAGE. Here is an illustration for the story from the 1574 edition of Osius:
What follows is an unmarked version of the prose rendering to faciliate word searches: Quia Asellus pelle Leonina se velarat, hac fraude homines et ferae pariter pavent. specie decepti credebant esse Leonem, haec res timore gravi digna visa fuit. at aures longae spectantibus produnt Asinum, qui more tali superbus stolide erat. unde agnitus cogitur pistrini labores graves ferre, facta proterva hanc poenam movent. ut tempus quondam honores indignis praebeat subito his dedecus, quod fuit ante, redit. ut superbia stulta laudem vanam sibi arroget, fraude patente, laus ea tamen crimen erit.