Agni Purana (Jyotisha Selections) · by Vyasa
Chapter 5 · Omens
शकुनानि
जलोपवेशनं नेष्टं भूमौ च परिवर्तनम् ।विपत्करं तुरंगस्य सुप्तं वाऽप्यनिमित्ततः ॥ २६ ॥
In the full Agni Purana this is chapter 232, verse 26.
Sitting down in water is not wanted, nor rolling on the ground. Sleeping for no reason also brings trouble to a horse.
Simple meaning: A horse sitting in water, rolling on the ground or sleeping for no reason brings trouble.
यवमोदकयोर्द्वेषस्त्वकस्माच्च न शस्यते ।
A horse suddenly refusing barley and sweets, bleeding from the mouth, or trembling is a bad sign.
क्रीडन्वकैः कपोतैश्च सारिकाभिर्मृतिं वदेत् ।
A horse playing with herons, pigeons or mynas points to death. Tears and foot-licking point to ruin.
वामपादेन च तथा विलिखंश्च वसुंधराम् ।
A horse scratching the ground with its left foot, sleeping on its left side or by day, is not good.