When I breed cows in an automatic cow farm (with water to push the new babies across) the babies seem to get stuck somewhere and begin to suffocate and die. Pistons and water cannot push the babies through a 1 high gap without them dying it seems.
Environment
Windows 8, 64 bit Java (Newest Version)
Likely dupe of MC-2025, although there are design changes you can do to minimize it (i.e. use glass blocks or fences).