If you want to involve the guys then I would set up games in the back like horse shoes, darts, volleyball, bocci ball, and so forth with some beer or beverages in a cooler...they probably won't want to watch the whole present opening thing...but a contest where the guys are blindfolded and have to change a doll's diaper might be hysterical. Give each man a babydoll with dirty diaper and a pile of little clothes. They have to change the diaper and dress the baby blindfolded.
Ideas:
Have everyone bring a farm animal stuffed animal with their gift.
Have everyone bring a book that involves farm animals for the baby's library.
Games that are always played in our family:
guess the number of jelly beans in the bottle...then you get the bottle (can use other types of candy)
Prize for person sitting in the chair with a sticker tapes under their chair.
Make little diaper corsages to pin on everyone when they arrive...the one with the poopie stain inside gets a prize.
Put wooden clothes pins on a coat hanger. Everyone takes turns grabbing the pins off the hanger with one hand. The woman that can grab the most pins from the hanger without dropping them wins.
Have each woman take turns holding a child on their hip, a phone on their ear, and a basket of clothes that they have to try to hang on a line at the same time. Time each woman and the one that can hang them all in the least amount of time wins. (they have to carry on an imaginary conversation as well)
Put about 15 baby type items on a tray (little diaper, diaper creme, baby food, pacifier...). Cover with a cloth. Each group of ladies gets 30 seconds to look at the platter and then they have to try to write down as many things as they can remember when you leave. The one that can remember the most wins a prize. New mom gets the platter of goodies when the game is over.
Pass around a roll of toilet paper to all the women and they must tear off a piece that they think will fit neatly around the pregnant mom from belly button around the middle of the back and back to the belly button. The one that gets closest to a perfect fit wins.
Make up a word list of baby related words that you scramble. Give a copy to each attendee and then give them so many minutes to unscramble as many as possible.
Every attendee gets a curly ribbon with a play plastic pacifier or saftey pin attached. Instruct everyone they can't use the word baby. If they hear someone say baby they can take their necklace. The one with the most at the end of the shower wins.
Make a punch with ice cubes. Freeze a tiny plastic baby in one ice cube...the one that gets the baby wins. A variation involves the cake. Have a tiny baby inserted in the cake before it is frosted. The person that gets the baby wins a prize. (make sure to warn everyone before they eat their cake)
Have everyone come dressed as a farmer/farmer brown style. Then have guests vote for the best dressed who will recieve a prize....(movie tickets, a gift certificate to a bbq place, or so forth...something kinda nice)
Prizes can be the centerpieces on the tables....The last shower I went to they had nice votive candle holders as centerpieces and gave those away as prizes to those that had stickers under their seats.
Make chocolate baby suckers, chocolate baby bottles, and so forth to give away in little chinese takeout boxes.
Use fresh flowers in cute little vases on the tables and give those away to guests that win games. You can also use little potted veggies, herbs, or even just little potted flowers. Plant them in little painted clay pots or just wrap the little plastic pots they came in with decorative tissue, wrapping paper or sit down in little chinese takeout cartons.
Give away nicely frosted farm animal shaped cookies to support the theme.
Decorations:
Make a gingerbread house but in the shape of a barn for the cake table.
Make a diaper cake out of disposable diapers for the present table.
Find a little hay bale and then decorate with a tiny wheelbarrel, some squash, corn on the cob, some of the stuffed animals that people bring.
Hope you can get something out of that....Good luck and have fun. I recommend doing a Google search with words and phrases like...."farm animal baby shower" and so forth.