I have 7 darling duckilings in a big water trough in the basement under a light. 3 of the 7 are about 2 weeks old while the other 4 are only a few days old. The problem is they are crazy messy. I need brooder advice...how long do they need to stay under the light? When can I move them out to the duck house? The evenings here are are getting as low as like 35-40s. Is that too cold?