We had 8 guineas just a few days ago, healthy and acting fine. They share a house with some baby ducks right now. In the last two days, four guineas have died. They do not act sick and we’re walking around just fine and eating and drinking. We thought it may be too cold so we added a second heat lamp and they’ve been fine. Any thoughts as to what is going on?? I don’t want to lose my other ones!!!