Moving the weaned calf from an individual hutch to a group pen can be a stressful time. Therefore, the transition pen should be as comfortable and "calf friendly" as possible. The calf needs to adjust to being with other calves and adapt to eating from a bunk and drinking from a waterer. Freestalls add one more stress to the newly weaned calf, i.e., adapting to lying in freestalls. Transition housing should provide a resting condition similar to the hutch. Small group size is also recommended (fewer than 10 calves). With that said, on occasion I see producers use freestalls immediately after weaning. These producers do an extremely good job of providing comfortable, well-bedded straw stalls and vigilant observation to make sure the calves were adapting without undue stress.

Dave Fischer, Extension Dairy Educator, University of Illinois - Illini DairyNET

I agree the move from individual to group housing can be a stressful time for weaned heifers. A clean, dry, comfortable bedded pen is typically the best choice for housing weaned heifers up to 4 to 6 months of age. Provide approximately 40 square feet of bedded area and 18 inches of feeding space per head. Remove soiled bedding and replace it with clean, dry bedding rather than add clean bedding on top of soiled bedding. Facility plans for weaned heifer housing can be found at: http://www.abe.psu.edu/extension/ip/DIPlevel2replacement.html.

Heifers that are 4 to 6 months old seem to adapt better to freestalls. Be sure to select dimensions based on the size of the heifers that will leave the group rather than the size at group entry. Larger dimensions accommodate smaller heifers better than vice versa. Suggested freestall sizes for older heifers can be found at: http://www.abe.psu.edu/extension/ip/dippdfs/dip822.pdf.

Dan McFarland, Senior Extension Educator - Agricultural Engineering, Penn State Cooperative Extension