Rule of thumb is they can hold their bladder for an hour for every month in age they are, 3 mos. 3 hours, etc. etc.
The obedience trainer we had for our outside dogs, has 4 dogs of his own, he said they eat in their crates..I took my 12 week old in for her shots yesterday, I know the vet told me to make sure (with these dogs being so small) to have food down 24/7 for them until they get older..here's a website on crate training..good luck with your baby
http://www.inch.com/~dogs/cratetraining.html