Which of the following is a sign of hypercalcemia?

Poor feeding is indeed a sign of hypercalcemia, particularly in neonates. Hypercalcemia can lead to lethargy, decreased appetite, and poor feeding behaviors due to its effects on neuromuscular function and overall metabolic processes. High calcium levels can interfere with the neurological system, which may cause infants to feel weak or lethargic, resulting in a diminished desire to feed.

In contrast, increased muscle tone is not typically associated with hypercalcemia; instead, it may relate to conditions such as hypo/hypernatremia or neurological issues. High fever is generally a sign of infection or other inflammatory processes, rather than hypercalcemia. Severe crying is often a response to discomfort or distress, but does not specifically indicate high calcium levels. Overall, poor feeding aligns with the physiological effects hypercalcemia has on a neonate's metabolism and behavior.