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 (note the short final o in pavo):
Pāvo gravēs habuit cōram Iūnōne querēlās,

Quod cum formōsīs adeō sit praedita pennīs,

Vōce tamen valeat cum parva volucris Aēdon,

Cuī, rectē, Dea dīxit, erat pār omnia nullī

PROSE MACRONS. Here is the same text with macrons written out in prose word order:
Pāvo querēlās gravēs habuit cōram Iūnōne cūius Deae illa avis propria dīcitur: Quod cum praedita sit pennīs adeō formōsīs ope gutturis argūtī destituātur. cum tamen Aēdon, parva volucris, valeat vōce quam haec variāre sciat modīs innumerīs. Cuī, rectē, Dea dīxit: Pār erat omnia nullī attribuī; iūstō dēsine plūra petās.
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):
Pavo querélas graves hábuit coram Iunóne cuius Deae illa avis própria dícitur: Quod cum praédita sit pennis ádeo formósis ope gútturis argúti destituátur. Cum tamen Aedon, parva vólucris, váleat voce quam haec variáre sciat modis innúmeris. Cui, recte, Dea dixit: Par erat ómnia nulli attríbui; iusto désine plura petas.
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.
Pāvo gra·vēs habu·it cō·ram Iū·nōne que·rēlās,

Quod cum ·formō·sīs ade·ō sit· praedita· pennīs,

Vōce ta·men vale·at cum· parva vo·lucris A·ēdon,

Cuī, rec·tē, Dea· dīxit, e·rat pār· omnia ·nullī

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: Pavo querelas graves habuit coram Iunone cuius Deae illa avis propria dicitur: Quod cum praedita sit pennis adeo formosis ope gutturis arguti destituatur. cum tamen Aedon, parva volucris, valeat voce quam haec variare sciat modis innumeris. Cui, recte, Dea dixit: Par erat omnia nulli attribui; iusto desine plura petas.