I'm so sorry! With two deaths around the same time, I would wonder about something environmental... could they have eaten something? Sudden temperature change? Air impurities? New cleaning products in the immediate vicinity? I would also wonder about something communicable that spread very quickly, before you could see any signs, like a really nasty respiratory infection, which can make pigs go from zero to passing away within hours (the last piggie I lost from a respiratory bug was fine in the morning, seemed lethargic in the afternoon, passed in the evening despite a vet visit/antibiotics.) Again, ((HUGS)) and so sorry, it's hard when there's no obvious reason for their passing and losing two so quickly is especially heartbreaking!