If they appear so, it is time to call your veterinarian. Straining to defecate or urinate. Swollen, moist, leaking umbilical cord. Foal wanders away from the mare or in unaware of the mare in the stall. Poor suckle reflex.
Placenta is thickened, discolored.
While we spend alot of time looking at the foal, don't forget that the mare can give you an indication that the foal is becoming ill before the foal shows a significant change in character. Examine the udder, milk, and vulva for signs of disease or infection. A full tight udder indicates a foal that isn't nursing. Malodorous uterine discharge may indicate the foal has an infection which developed in utero. It is likely that the physical abnormalities associated with trauma constitute an emergency and need not be covered, except your initial management until the vet arrives.